Originally Posted by 14pilot
The stock exhaust does not restrict flow or performance until you get up to around 680rwhp. This was documented by Ted of JRE about 3 years ago if you care to search back that far.
SOooo... if you buy an aftermarker catback, axleback or get the optional NPP exhuast, do it for the sound. That's all that is going to change.
Aftermarket manufacturers have reported BS gains ever since the first aftermarket was released.
This is total bullcrap! A 3" X pipe exhuast will make power over the stock exhaust in propbably even a mild bolton car. Explain why my car picked up 2mph with nothing but swaping 1 chamber flowmasters to 3" glasspacks! Dont bother saying weather, because it was in simular conditions and I noticed an increas in performance right away! Plain and simple, they flow better... the stock exhaust is not going to match a good aftermarket systeme, I dont care what test say.