diff --git a/NBToolkit/BlockFilter.cs b/NBToolkit/BlockFilter.cs
index 8db6423..808e567 100644
--- a/NBToolkit/BlockFilter.cs
+++ b/NBToolkit/BlockFilter.cs
@@ -28,6 +28,9 @@ namespace NBToolkit
         int ExcludedBlockCount { get; }
 
         double? ProbMatch { get; }
+
+        bool IncludedBlocksContains (int id);
+        bool ExcludedBlocksContains (int id);
     }
 
     public class BlockFilter : IOptions, IBlockFilter
@@ -51,11 +54,13 @@ namespace NBToolkit
         public int? XAboveEq
         {
             get { return _xAboveEq; }
+            set { _xAboveEq = value; }
         }
 
         public int? XBelowEq
         {
             get { return _xBelowEq; }
+            set { _xBelowEq = value; }
         }
 
         public int? YAboveEq
@@ -130,8 +135,24 @@ namespace NBToolkit
                     v => _invertXYZ = true },
                 { "bi|BlockInclude=", "Match blocks of type {ID}.  This option is repeatable.",
                     v => _includedBlocks.Add(Convert.ToInt32(v) % 256) },
+                { "bir|BlockIncludeRange=", "Match blocks of type between {0:V1} and {1:V2}, inclusive.  This option is repeatable.",
+                    (v1, v2) => {
+                        int i1 = Math.Max(0, Math.Min(255, Convert.ToInt32(v1)));
+                        int i2 = Math.Max(0, Math.Min(255, Convert.ToInt32(v2)));
+                        for (int i = i1; i <= i2; i++) {
+                            _includedBlocks.Add(i);
+                        }
+                    } },
                 { "bx|BlockExclude=", "Match all blocks except blocks of type {ID}.  This option is repeatable.",
                     v => _excludedBlocks.Add(Convert.ToInt32(v) % 256) },
+                { "ber|BlockExcludeRange=", "Match all blocks except blocks of type between {0:V1} and {1:V2}, inclusive.  This option is repeatable.",
+                    (v1, v2) => {
+                        int i1 = Math.Max(0, Math.Min(255, Convert.ToInt32(v1)));
+                        int i2 = Math.Max(0, Math.Min(255, Convert.ToInt32(v2)));
+                        for (int i = i1; i <= i2; i++) {
+                            _excludedBlocks.Add(i);
+                        }
+                    } },
                 { "bp|BlockProbability=", "Selects a matching block with probability {VAL} (0.0-1.0)",
                     v => _prob = Convert.ToDouble(v) },
             };
@@ -153,5 +174,15 @@ namespace NBToolkit
             Console.WriteLine("Block Filtering Options:");
             _options.WriteOptionDescriptions(Console.Out);
         }
+
+        public bool IncludedBlocksContains (int id)
+        {
+            return _includedBlocks.Contains(id);
+        }
+
+        public bool ExcludedBlocksContains (int id)
+        {
+            return _excludedBlocks.Contains(id);
+        }
     }
 }
diff --git a/NBToolkit/ChunkFilter.cs b/NBToolkit/ChunkFilter.cs
index c832f3a..4d0bd7d 100644
--- a/NBToolkit/ChunkFilter.cs
+++ b/NBToolkit/ChunkFilter.cs
@@ -31,6 +31,9 @@ namespace NBToolkit
         bool ExcludeMatchAll { get; }
 
         double? ProbMatch { get; }
+
+        bool IncludedBlocksContains (int id);
+        bool ExcludedBlocksContains (int id);
     }
 
     public class ChunkFilter : IOptions, IChunkFilter
@@ -55,21 +58,25 @@ namespace NBToolkit
         public int? XAboveEq
         {
             get { return _xAboveEq; }
+            set { _xAboveEq = value; }
         }
 
         public int? XBelowEq
         {
             get { return _xBelowEq; }
+            set { _xBelowEq = value; }
         }
 
         public int? ZAboveEq
         {
             get { return _zAboveEq; }
+            set { _zAboveEq = value; }
         }
 
         public int? ZBelowEq
         {
             get { return _zBelowEq; }
+            set { _zBelowEq = value; }
         }
 
         public bool InvertXZ
@@ -167,5 +174,15 @@ namespace NBToolkit
             Console.WriteLine("Chunk Filtering Options:");
             _options.WriteOptionDescriptions(Console.Out);
         }
+
+        public bool IncludedBlocksContains (int id)
+        {
+            return _includedBlocks.Contains(id);
+        }
+
+        public bool ExcludedBlocksContains (int id)
+        {
+            return _excludedBlocks.Contains(id);
+        }
     }
 }
diff --git a/NBToolkit/Dump.cs b/NBToolkit/Dump.cs
index 3190f6b..1d7f8a1 100644
--- a/NBToolkit/Dump.cs
+++ b/NBToolkit/Dump.cs
@@ -4,7 +4,8 @@ using System.Text;
 using System.IO;
 using NDesk.Options;
 using Substrate;
-using Substrate.NBT;
+using Substrate.Nbt;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -96,7 +97,7 @@ namespace NBToolkit
 
         public override void Run ()
         {
-            INBTWorld world = GetWorld(opt);
+            NbtWorld world = GetWorld(opt);
             IChunkManager cm = world.GetChunkManager(opt.OPT_DIM);
             FilteredChunkManager fcm = new FilteredChunkManager(cm, opt.GetChunkFilter());
 
diff --git a/NBToolkit/FilteredChunkManager.cs b/NBToolkit/FilteredChunkManager.cs
index b6169b1..99ba058 100644
--- a/NBToolkit/FilteredChunkManager.cs
+++ b/NBToolkit/FilteredChunkManager.cs
@@ -3,6 +3,7 @@ using System.Collections;
 using System.Collections.Generic;
 using System.Text;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -230,5 +231,15 @@ namespace NBToolkit
         }
 
         #endregion
+
+        #region IChunkContainer Members
+
+
+        public bool CanDelegateCoordinates
+        {
+            get { return false; }
+        }
+
+        #endregion
     }
 }
diff --git a/NBToolkit/GenOres.cs b/NBToolkit/GenOres.cs
index 18681f7..51727d7 100644
--- a/NBToolkit/GenOres.cs
+++ b/NBToolkit/GenOres.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Text;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -100,8 +101,8 @@ namespace NBToolkit
                                 for (int iz = zStart; iz <= zEnd; iz++) {
                                     double zThresh = (iz + 0.5D - zPos) / (fuzzXZ / 2.0D);
                                     if (xThresh * xThresh + yThresh * yThresh + zThresh * zThresh < 1.0D) {
-                                        BlockRef block = blockMan.GetBlockRef(ix, iy, iz);
-                                        if (block != null) {
+                                        AlphaBlockRef block = blockMan.GetBlockRef(ix, iy, iz);
+                                        if (block.IsValid) {
                                             block.ID = _blockId;
                                             block.Data = _blockData;
                                         }
diff --git a/NBToolkit/Oregen.cs b/NBToolkit/Oregen.cs
index b632298..56b91a8 100644
--- a/NBToolkit/Oregen.cs
+++ b/NBToolkit/Oregen.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using NDesk.Options;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -181,7 +182,7 @@ namespace NBToolkit
 
         public override void Run ()
         {
-            INBTWorld world = GetWorld(opt);
+            NbtWorld world = GetWorld(opt);
             IChunkManager cm = world.GetChunkManager(opt.OPT_DIM);
             FilteredChunkManager fcm = new FilteredChunkManager(cm, opt.GetChunkFilter());
 
@@ -205,7 +206,7 @@ namespace NBToolkit
             Console.WriteLine("Affected Chunks: " + affectedChunks);
         }
 
-        public void ApplyChunk (INBTWorld world, ChunkRef chunk)
+        public void ApplyChunk (NbtWorld world, ChunkRef chunk)
         {
             if (opt.OPT_V) {
                 Console.WriteLine("Generating {0} size {1} deposits of {2} between {3} and {4}",
@@ -265,7 +266,7 @@ namespace NBToolkit
                 return false;
             }
 
-            int blockID = _cache.Blocks.GetID(x & _chunkXMask, y & _chunkYMask, z & _chunkZMask);
+            int blockID = cache.Blocks.GetID(x & chunkXMask, y & chunkYMask, z & chunkZMask);
 
             if (
                 ((opt.OPT_OA) && (blockID != opt.OPT_ID)) ||
diff --git a/NBToolkit/Purge.cs b/NBToolkit/Purge.cs
index 79df1e6..f73a3c9 100644
--- a/NBToolkit/Purge.cs
+++ b/NBToolkit/Purge.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using NDesk.Options;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -69,7 +70,7 @@ namespace NBToolkit
 
         public override void Run ()
         {
-            INBTWorld world = GetWorld(opt);
+            NbtWorld world = GetWorld(opt);
             IChunkManager cm = world.GetChunkManager(opt.OPT_DIM);
             FilteredChunkManager fcm = new FilteredChunkManager(cm, opt.GetChunkFilter());
 
diff --git a/NBToolkit/Relight.cs b/NBToolkit/Relight.cs
index 5bf5dcc..c4835c3 100644
--- a/NBToolkit/Relight.cs
+++ b/NBToolkit/Relight.cs
@@ -3,6 +3,7 @@ using System.Collections.Generic;
 using System.Text;
 using NDesk.Options;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -11,9 +12,9 @@ namespace NBToolkit
         private OptionSet _filterOpt = null;
         private ChunkFilter _chunkFilter = null;
 
-        public bool BlockLight;
-        public bool SkyLight;
-        public bool HeightMap;
+        public bool BlockLight = false;
+        public bool SkyLight = false;
+        public bool HeightMap = false;
 
         public RelightOptions ()
             : base()
@@ -82,7 +83,7 @@ namespace NBToolkit
 
         public override void Run ()
         {
-            INBTWorld world = GetWorld(opt);
+            NbtWorld world = GetWorld(opt);
             IChunkManager cm = world.GetChunkManager(opt.OPT_DIM);
             FilteredChunkManager fcm = new FilteredChunkManager(cm, opt.GetChunkFilter());
 
diff --git a/NBToolkit/Replace.cs b/NBToolkit/Replace.cs
index 327f300..dc1aa85 100644
--- a/NBToolkit/Replace.cs
+++ b/NBToolkit/Replace.cs
@@ -4,6 +4,7 @@ using System.Text;
 using System.Globalization;
 using NDesk.Options;
 using Substrate;
+using Substrate.Core;
 
 namespace NBToolkit
 {
@@ -134,6 +135,23 @@ namespace NBToolkit
 
                 throw new TKOptionException();
             }
+
+            if (_blockFilter.XAboveEq != null) {
+                int cx = (int)_blockFilter.XAboveEq >> 5;
+                _chunkFilter.XAboveEq = Math.Max(_chunkFilter.XAboveEq ?? cx, cx);
+            }
+            if (_blockFilter.XBelowEq != null) {
+                int cx = (int)_blockFilter.XBelowEq >> 5;
+                _chunkFilter.XBelowEq = Math.Min(_chunkFilter.XBelowEq ?? cx, cx);
+            }
+            if (_blockFilter.ZAboveEq != null) {
+                int cx = (int)_blockFilter.ZAboveEq >> 5;
+                _chunkFilter.ZAboveEq = Math.Max(_chunkFilter.ZAboveEq ?? cx, cx);
+            }
+            if (_blockFilter.ZBelowEq != null) {
+                int cx = (int)_blockFilter.ZBelowEq >> 5;
+                _chunkFilter.ZBelowEq = Math.Min(_chunkFilter.ZBelowEq ?? cx, cx);
+            }
         }
 
         public IChunkFilter GetChunkFilter ()
@@ -153,30 +171,38 @@ namespace NBToolkit
 
         private static Random rand = new Random();
 
+        private List<BlockKey>[] _sort = new List<BlockKey>[256];
+
         public Replace (ReplaceOptions o)
         {
             opt = o;
+
+            for (int i = 0; i < 256; i++) {
+                _sort[i] = new List<BlockKey>();
+            }
         }
 
         public override void Run ()
         {
-            INBTWorld world = GetWorld(opt);
+            NbtWorld world = GetWorld(opt);
             IChunkManager cm = world.GetChunkManager(opt.OPT_DIM);
             FilteredChunkManager fcm = new FilteredChunkManager(cm, opt.GetChunkFilter());
 
             int affectedChunks = 0;
             foreach (ChunkRef chunk in fcm) {
-                affectedChunks++;
+                if (opt.OPT_V) {
+                    Console.WriteLine("Processing chunk {0},{1}...", chunk.X, chunk.Z);
+                }
 
                 ApplyChunk(world, chunk);
 
-                fcm.Save();
+                affectedChunks += fcm.Save() > 0 ? 1 : 0;
             }
 
             Console.WriteLine("Affected Chunks: " + affectedChunks);
         }
 
-        public void ApplyChunk (INBTWorld world, ChunkRef chunk)
+        public void ApplyChunk (NbtWorld world, ChunkRef chunk)
         {
             IBlockFilter opt_b = opt.GetBlockFilter();
 
@@ -195,7 +221,7 @@ namespace NBToolkit
             }
 
             xmin = (xmin < 0) ? 0 : xmin;
-            xmax = (xmin > 15) ? 15 : xmax;
+            xmax = (xmax > 15) ? 15 : xmax;
 
             if (xmin > 15 || xmax < 0 || xmin > xmax) {
                 return;
@@ -228,7 +254,7 @@ namespace NBToolkit
             }
 
             zmin = (zmin < 0) ? 0 : zmin;
-            zmax = (zmin > 15) ? 15 : zmax;
+            zmax = (zmax > 15) ? 15 : zmax;
 
             if (zmin > 15 || zmax < 0 || zmin > zmax) {
                 return;
@@ -238,8 +264,52 @@ namespace NBToolkit
             int ydim = chunk.Blocks.YDim;
             int zdim = chunk.Blocks.ZDim;
 
-            // Process Chunk
+            // Bin blocks
             for (int y = ymin; y <= ymax; y++) {
+                for (int x = xmin; x <= xmax; x++) {
+                    for (int z = zmin; z <= zmax; z++) {
+                        int id = chunk.Blocks.GetID(x, y, z);
+                        _sort[id].Add(new BlockKey(x, y, z));
+                    }
+                }
+            }
+
+            // Process bins
+            for (int i = 0; i < 256; i++) {
+                if (_sort[i].Count == 0) {
+                    continue;
+                }
+
+                if (opt_b.IncludedBlockCount > 0 & !opt_b.IncludedBlocksContains(i)) {
+                    continue;
+                }
+
+                if (opt_b.ExcludedBlockCount > 0 & opt_b.ExcludedBlocksContains(i)) {
+                    continue;
+                }
+
+                foreach (BlockKey key in _sort[i]) {
+                    chunk.Blocks.SetID(key.x, key.y, key.z, (int)opt.OPT_AFTER);
+
+                    if (opt.OPT_VV) {
+                        int gx = chunk.X * xdim + key.x;
+                        int gz = chunk.Z * zdim + key.z;
+                        Console.WriteLine("Replaced block {0} at {1},{2},{3}", i, gx, key.y, gz);
+                    }
+
+                    if (opt.OPT_DATA != null) {
+                        chunk.Blocks.SetData(key.x, key.y, key.z, (int)opt.OPT_DATA);
+                    }
+                }
+            }
+
+            // Reset bins
+            for (int i = 0; i < 256; i++) {
+                _sort[i].Clear();
+            }
+
+            // Process Chunk
+            /*for (int y = ymin; y <= ymax; y++) {
                 for (int x = xmin; x <= xmax; x++) {
                     for (int z = zmin; z <= zmax; z++) {
                         // Probability test
@@ -301,7 +371,7 @@ namespace NBToolkit
                         }
                     }
                 }
-            }
+            }*/
         }
     }
 }
diff --git a/NBToolkit/TKFilter.cs b/NBToolkit/TKFilter.cs
index 41a5775..2de1a21 100644
--- a/NBToolkit/TKFilter.cs
+++ b/NBToolkit/TKFilter.cs
@@ -11,9 +11,9 @@ namespace NBToolkit
 
         public abstract void Run ();
 
-        public INBTWorld GetWorld (TKOptions opt)
+        public NbtWorld GetWorld (TKOptions opt)
         {
-            INBTWorld world = null;
+            NbtWorld world = null;
             try {
                 if (opt.OPT_ALPHA) {
                     world = AlphaWorld.Open(opt.OPT_WORLD);