RM Stainless Headers:

Excellent mod, great performance, dealer installed. $1,499. Just days after the purchase of my '91 NSX, I called Randy at RM Racing to see what we could do to bump up the horse power a notch. We did the headers, exhaust and clutch at that time. Top notch advice, great product, excellent customer service and they were willing to work with the dealer's NSX tech to make sure it all went smoothly.

Why the hell don't all auto manufacturers just put headers on their cars and call it a day? Better power, better mileage, better sound. Am I missing something?