I installed the ITG air filter on my C-Coupe (with ASP pulley) and I can feel an increase. At high rpm, like doing 40mph in second at WOT, the tires chirped. It didn't do that before. I've done dyno's before on this car with the factory air filter and no air filter and got 5.9hp and 2 ft-lbs torque and I'm guessing that this filter is capturing most of that gain. Worth the $50.