well i have a baseline dyno and a tuned dyno that shows an 18 whp improvement. that's pretty hard evidence. but i doubt i'll ever go to a quarter mile track again, after one NASA event im hooked. i passed an evo 9 pretty nicely in the turns, its fun when it comes down to skill and not the car. but that being said, i don't need any k and n's cuz my lease is up in 3 months and then its time for ME to get an evo 9 rs.