For those who want best performance. Do pullies, drop in filter, xpipe, and a tune. That will get u well over 380 to te wheels. Here is the price breakdown.
Pullies 400. Filter 100. tune 1000. turner test pipes whi h eliminate stock cats 400 or xpipe with hfc 2000.
As u can see u can get. Lot more out of our m3 with a light budget.