has a bunch of yack about air intakes/exhausts/chips/superchargers etc. and you should probably read it over. (It's also got some snarkiness going on between members about the upcoming Wrangler engine, but ignore that.
The bottom line is that nothing will even approach the Ripp. That's going to put over 100 more hp at your wheels. Regearing would be next on the list in terms of realizable power, but it sure isn't going to be anywhere near 100 hp. Then you've got the intakes/exhausts/etc. etc., which may--it's endlessly debated--add just a handful of ponies. The only caveat to all that is if you've got an auto transmission, in which case a superchip flashpaq is indeed a good idea.