Hah- my personal favorite was duct taping a turkey call over the blow-off valve on my old racecar- BEST mod ever!!! I definitely won a few races and overtakes just from making my opponents laugh their asses off. Never got old in dozens of races
Also, the effects most folks feel from CAI's on the JK is what I refer to as NP- NoisePower (or NoPower). Nothing to do with HP (HorsePower), it's an increase in noise, and a decrease in funds, which makes people dearly hope they've gained HP. Usually all in their heads.
There are 4 ways to make ANY noticable gains in HP with the JK's:
1. Superchips- best, and cheapest
2. Re-gear- 2nd best, 2nd cheapest- great idea if you go off-road, not so great if you worry about warranty (more on that later)
3. Supercharger- not worth the $
4. Hemi swap- $$$$$$$$$$$$$, but SICK
As for warranty, run a search on the Magnuson Moss Act of 1979. Search on here. There are plenty of answers to this question, and more- just a click and a few letters away- like magic!
Cheers- Mark W.