A long time ago, I've shared with some fellows that is possible to serve compressed (gz) files directly from Apache, and save some network bandwidth with it.
I more used to Nginx, so I confess that achieve this with Apache was a little trickier.
After some tweaking over my Apache virtual host configuration, using mode deflate to serve the compressed assets I got a problem. My files seems to be compressed twice. Googling a little I found this stackoverflow answer http://stackoverflow.com/a/7510773/537235 that solve my problem.
If you're using Rails and precompile your assets, so it will minify and compress for you. Therefore you are not required to config Apache's mode deflate, because you will be serving pre-compressed content, instead of compress during the request time, which could be expensive for you server.
The following solution works fine with virtual host configuration of .htaccess. It's not usual for me put a .htaccess file inside public/assets folder in a Rails application, so, I did it using the virtual host.
I hope this help you too.