it dosnt do shit... trust me, I've been there done that.
worry about other things like an M50 engine or sumthin cause a 40 dollor fillter dosnt do shit,at least not by it self.
if u upgrade anything, make it be the suspention to begine with... your car will feel 100% different pluss it will felll soo much faster, especial on those bends
u could think about:
strieght pipe exhaust
<img src='http://freehost10.websamba.com/j2s325/schneider325.jpg' border='0' alt='user posted image' />
PATRIOT, n. One who loves his country, and zealously supports its authority
"I had made it clear to the world that either you're with us or you're with the enemy, and that doctrine still stands"