I've read so much about this that I just can't get an oppinion...

I know that a filter reduces the ability of the engine to "breath air" and, on a performance one that hopefully pulls more air into it, the probability of it restricting the air flow exists.

But what happens in our cosworths?

The pannel filter has a significant area and, acording to what i've heard, on a cossie airbox, a decent K&N panel filter should do the trick for a big HP engine.

I've had a K&N for 7 years now and never thought of changing it, I eventually clean it from time to time on the dish washer when the missys not at home , but am i better of leaving it alone? or should i get a benefit from changing it?

Don't get me wrong... I'm not a noob. I know there is much more than just air flow like angles, turbulence, etc... But what do the experts say? is it worth the money?

I'm on greens with about 340bhp