When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
I've noticed minimal gains in the header portion but lost of torque since you're removing a lot of backpressure that N/A cars tend to need. I would say high flow cats, test-pipes and some sort of catback exhaust would make the most reliable power.