dude, what kind of car do you have first of all?
.......also, remember, when modding your car, its a balancing act. you could gain hp by freeing up the intake, but that increase in power will result in a decrease somewhere else in the power band. you'll eventually want to look at free'ing up the exhaust, and chipping it. makes it more well rounded. ...just my opinion.
check out: http://www.bavarianautosport.com/
here's a good site, that lets you manipulate stats on your car, and race against others: http://www.cartestsoftware.com/
another good one: http://dinancars.com/default.htm http://www.europersona.com/bmw.htm http://www.hmsmotorsport.com/store.php
AH what the hell, here's a zip file with ALL of my Bimmer Links attached: Download the attachment below...
<p align="center"><b><font size="2" face="Copperplate31ab">We're on your ass BENNY-BOY!!!!</font></b></p>
<p align="center"><img border="0" src="http://www.geocities.com/torrienta/U...yF16.jpg"