I've purchased two cars in the past upon which the POs had installed K&Ns: A 400HP Jaguar XKR and a 300+HP Modified Roadmaster Station Wagon (it was a wicked car - lol). In both cases I removed the filters as soon as I was aware of them. I wasn't going to expose either a Supercharged Jaguar or LT1 engine to the extra grit the K&Ns let through. I typically keep my cars for a very, very long time (100K+ miles), so the minuscule extra horsepower isn't worth the risk to engines' longevity. I'd never even consider installing them in the 360, nor any possible future 430/458. I take care of my engines.