Our Cars have Sensors and Fuel Injection that will compensate for any changes of Air Intake
I'm of the same mind as John in that I don't see the K&N as a "Performance Upgrade" in the way that term is used - i.e remapping would be a "Performance Upgrade" - However, our Engines Run on AIR - Petrol/Diesel/LPG whatever are just Primers (Air/Fuel ratios are the clue) less restriction = less output power required to feed the same volume of Air = Performance Benefit
Improved Throttle Response may Not affect Peak Figures - any little improvement here will be noticed by all but the most Numb drivers tho
I'm sure the K&N will be Noticeable Improvement to all but the most Numb and those who expect similar results to remapping
Paul.