Glad you asked... I have had a K&N Aircharger on my Ford Focus (daily driver) for four years now. I am so in love with the K&N Aircharger that I just ordered one for my C6 (and it arrived yesterday!!).
Immediate results - Noticeably quicker throttle response, you'll be able to see it on your tach right away. The needle jumps much quicker. Also, the beautiful sound!! Its not a gaudy ricer noise, its a deep sucking sound that lets you know your engine is breathing better. Combine that with a set of stingers out the back and you are set:thumbsup:
Long Term Results - Better Gas Mileage (probably 2mpg better), no wasted money on a new filter every few oil changes, less wear and tear on the motor since the oil filtration element actually keeps crap out.
Just my .02:buhbye: