diff --git a/CHANGES b/CHANGES
--- a/CHANGES
+++ b/CHANGES
@@ -1,3 +1,14 @@
+* 0.1.4.3 (7 June 2012)
+
+  - Import 'build' function from GHC.Exts instead of defining it by
+    hand, which can lead to some speedups (since GHC has special
+    rewriting rules for the version in GHC.Exts).  Of course this ties
+    it to GHC; if you want to build split under some other compiler,
+    let me know and I can add some CPP directives to define 'build'
+    conditionally.
+
+  - Remove unnecessary Rank2Types extension.
+
 * 0.1.4.2 (21 December 2011)
 
   - Bump version upper bound for base and Test with GHC 7.4.1rc1
diff --git a/Data/List/Split.hs b/Data/List/Split.hs
--- a/Data/List/Split.hs
+++ b/Data/List/Split.hs
@@ -4,8 +4,8 @@
 -- Copyright   :  (c) Brent Yorgey, Louis Wasserman 2008
 -- License     :  BSD-style (see LICENSE)
 -- Maintainer  :  Brent Yorgey <byorgey@gmail.com>
--- Stability   :  experimental
--- Portability :  unportable (GADTs, Rank2Types)
+-- Stability   :  stable
+-- Portability :  GADTs
 --
 -- The "Data.List.Split" module contains a wide range of strategies
 -- for splitting lists with respect to some sort of delimiter, mostly
diff --git a/Data/List/Split/Internals.hs b/Data/List/Split/Internals.hs
--- a/Data/List/Split/Internals.hs
+++ b/Data/List/Split/Internals.hs
@@ -1,12 +1,12 @@
-{-# LANGUAGE GADTs, Rank2Types #-}
+{-# LANGUAGE GADTs #-}
 -----------------------------------------------------------------------------
 -- |
 -- Module      :  Data.List.Split.Internal
 -- Copyright   :  (c) Brent Yorgey 2008
 -- License     :  BSD-style (see LICENSE)
 -- Maintainer  :  byorgey@gmail.com
--- Stability   :  experimental
--- Portability :  unportable (GADTs, Rank2Types)
+-- Stability   :  stable
+-- Portability :  GADTs
 --
 -- Implementation module for "Data.List.Split", a combinator library
 -- for splitting lists.  See the "Data.List.Split" documentation for
@@ -17,6 +17,11 @@
 module Data.List.Split.Internals where
 
 import Data.List (genericSplitAt)
+import GHC.Exts  (build)
+  -- Use the build from GHC.Exts because GHC has some rules that make
+  -- it faster.  If you want to build split under some compiler other
+  -- than GHC, let me know; it would be easy to add some CPP
+  -- conditionally defining build.
 
 -- * Types and utilities
 
@@ -126,10 +131,6 @@
 isText (Text _) = True
 isText _ = False
 
--- | Standard build function.
-build :: (forall b. (a -> b -> b) -> b -> b) -> [a]
-build g = g (:) []
-
 -- * Implementation
 
 -- | Given a delimiter to use, split a list into an internal
@@ -494,8 +495,7 @@
 --   is total.
 splitPlaces :: Integral a => [a] -> [e] -> [[e]]
 splitPlaces is ys = build (splitPlacer is ys) where
-  splitPlacer :: forall i b t. Integral i
-              => [i] -> [b] -> ([b] -> t -> t) -> t -> t
+  splitPlacer :: Integral i => [i] -> [b] -> ([b] -> t -> t) -> t -> t
   splitPlacer [] _ _ n      = n
   splitPlacer _ [] _ n      = n
   splitPlacer (l:ls) xs c n = let (x1, x2) = genericSplitAt l xs
@@ -510,8 +510,7 @@
 -- > splitPlacesBlanks [4,9,3] [1..10] == [[1,2,3,4],[5,6,7,8,9,10],[]]
 splitPlacesBlanks :: Integral a => [a] -> [e] -> [[e]]
 splitPlacesBlanks is ys = build (splitPlacer is ys) where
-  splitPlacer :: forall i b t. Integral i
-              => [i] -> [b] -> ([b] -> t -> t) -> t -> t
+  splitPlacer :: Integral i => [i] -> [b] -> ([b] -> t -> t) -> t -> t
   splitPlacer [] _ _ n      = n
   splitPlacer (l:ls) xs c n = let (x1, x2) = genericSplitAt l xs
                               in  x1 `c` splitPlacer ls x2 c n
diff --git a/split.cabal b/split.cabal
--- a/split.cabal
+++ b/split.cabal
@@ -1,5 +1,5 @@
 Name:                split
-Version:             0.1.4.2
+Version:             0.1.4.3
 Stability:           stable
 Description:         Combinator library and utility functions for splitting lists.
 Homepage:            http://code.haskell.org/~byorgey/code/split