I'm looking for the best free implementation of deflate

[caveman]

Hello,
I'm trying to write an application for webdesigners that should produce the smallest PNG files and GZipped CSS or JavaScript files (.css.gz .js.gz).
The problem is that the best deflate implementatin I've found is the one included in KZIP and PNGOUT by Ken Silverman (closed source, and he has commercial interests in the PNGOUTWin app), zlib and even the deflate found in 7-zip are far from producing equivalent deflate streams.
Is there another state of the art deflate implementation I could use?
Any developpers around who would like to spend some time improving the current ones?

[Matt Mahoney]

kzip is the best in my benchmark. http://mattmahoney.net/dc/text.html
But as you can see, there is not much difference between kzip, gzip, gziphack, info-zip, jar, and peazip, which all use deflate.

[willvarfar]

You could move this one step further up - optimise the css and minimise the js before compression, then use a good-but-not-kzip e.g. 7zip. For PNG, why not just use PNGOUT as-is in binary form? And the same for KZIP?