Unless you're gonna stay N/A and add every single piece possible to your engine i'd say all headers are worthless. There are many 4.6 cars with 600hp+ still wearing the stock manifolds.

 

Well got my tuned length bbk shorties installed and I got to tell ya. They totally changed the sound it's alittle more crisp and little better throttle response. The seat of pants dyno not to much difference but hey I like them thus far.

 

Isn't "Noise" part of owning a Mustang???