Originally Posted by Sticky
Cat delete, 500 bucks.
yup, biggest gains on the m3 are found by deleting the cat and chipping to remap engine to freer flowing exhaust...
the bmw engineers had to pull a few tricks out of the bag to make this car meet California emissions standards (anyone notice how rough the car idles when cold? this is why...)
without knowing too much about the subject, I could safely say defeating some of these emissions controls (i.e Cat and o2 sensors) you would unlock some relatively significant gains (40-50hp) at the cost of making your car non-street legal .... then again, will cops really catch you on this?