diff --git a/package.json b/package.json
index 212e1618..fcb93ad6 100644
--- a/package.json
+++ b/package.json
@@ -49,13 +49,16 @@
     "browserify-istanbul": "^2.0.0",
     "bundle-collapser": "^1.2.1",
     "dependency-check": "^2.5.1",
+    "disc": "^1.3.2",
     "envify": "^3.4.1",
     "es2020": "^1.0.1",
     "geval": "~2.1.1",
+    "gzip-size-cli": "^1.0.0",
     "insert-css": "^0.2.0",
     "istanbul": "^0.4.4",
     "karma-sauce-launcher": "^1.0.0",
     "min-document": "~2.18.0",
+    "pretty-bytes-cli": "^1.0.0",
     "proxyquire": "~1.7.10",
     "proxyquire-universal": "~1.0.8",
     "proxyquireify": "~3.2.0",
diff --git a/scripts/build b/scripts/build
index c99a8072..28c2f802 100755
--- a/scripts/build
+++ b/scripts/build
@@ -14,6 +14,8 @@ build_dev () {
   NODE_ENV=development "$browserify" index.js \
     --standalone=choo \
     -t envify \
+    -g yo-yoify \
+    -g es2020 \
     > dist/choo.js
 }
 
@@ -23,7 +25,12 @@ build_min () {
     --standalone=choo \
     -t envify \
     -g unassertify \
+    -g yo-yoify \
+    -g es2020 \
     -g uglifyify \
+    -t envify \
+    -p bundle-collapser/plugin \
+    | uglifyjs \
     | "$uglify" \
     > dist/choo.min.js
 }
diff --git a/scripts/instrument b/scripts/instrument
index 123c132f..ced46c4e 100755
--- a/scripts/instrument
+++ b/scripts/instrument
@@ -1,5 +1,13 @@
 #!/bin/sh
 
+dirname=$(dirname "$(readlink -f "$0")")
+
+browserify="$dirname/../node_modules/.bin/browserify"
+uglify="$dirname/../node_modules/.bin/uglifyjs"
+pretty_bytes="$dirname/../node_modules/.bin/pretty-bytes"
+gzip_size="$dirname/../node_modules/.bin/gzip-size"
+discify="$dirname/../node_modules/.bin/discify"
+
 usage () {
 cat << USAGE
 script/test-size
@@ -10,38 +18,51 @@ script/test-size
 USAGE
 }
 
+# use zopfli for better compression if available
+gzip () {
+  zopfli -h 2>/dev/null
+  if [ $? -eq 0 ]; then
+    zopfli "$1" -i1000 -c | wc -c
+  else
+    "$gzip_size" < "$1"
+  fi
+}
+
 gzip_size () {
-  browserify index.js \
+  mkdir -p tmp/
+  "$browserify" index.js \
     -g unassertify \
     -g yo-yoify \
     -g es2020 \
     -g uglifyify \
     -p bundle-collapser/plugin \
-    | uglifyjs \
-    | gzip-size \
-    | pretty-bytes
+    | "$uglify" \
+    > tmp/bundle.min.js
+
+    gzip tmp/bundle.min.js | "$pretty_bytes"
+    rm -rf tmp/
 }
 
 min_size () {
-  browserify index.js \
+  "$browserify" index.js \
     -g unassertify \
     -g yo-yoify \
     -g es2020 \
     -g uglifyify \
     -p bundle-collapser/plugin \
-    | uglifyjs \
+    | "$uglify" \
     | wc -c \
-    | pretty-bytes
+    | "$pretty_bytes"
 }
 
 run_discify () {
-  browserify index.js --full-paths \
+  "$browserify" index.js --full-paths \
     -g unassertify \
     -g yo-yoify \
     -g es2020 \
     -g uglifyify \
-    | uglifyjs \
-    | discify --open
+    | "$uglify" \
+    | "$discify" --open
 }
 
 # set CLI flags