Just my opinion here. There isn't a car at the track that doesn't have a K & N in it. I use them in all of my cars. After putting one in my 300D turbo, I felt a marginal increase in power. Probably due to the fact that the turbo would spool up faster because of the reduced restriction. Other than that, no other change. It is recomended that the filter be washed every 10,000 miles. Most people wash them too often. Even a dirty K & N will flow better than a clean paper filter. It will probably filter better too. Anyway, IMHO, a K & N is worth the money one pays for it. It is a great addition to any car on the road and off. (By the way, I picked mine up at my local parts store. The price was $49.99. They even had them in stock!)