It depends on the ROM you want to use. Many of them are stripped down, in that they don't have a lot of add on apps. If you're looking to gain memory, this might be the type you seek. Something else you may want to do is run a clean up app on your device, if things are bogged down. Often, a system slowdown is caused by an accumulation of junk files, internet and otherwise. Check out MemMaid (
www.dinarsoft.com) or SKTools (
www.s-k-tools.com). Neither is free, but worth the $20 that you'll spend. If you're looking for ROM specific info, check over at
www.xda-developers.com