i have a 01 5.4l and i am looking for exhaust heard alot about magnaflow catback well how much hp and tq and gas mileage can i expect and also whats the difference in catback and regular cheaper magnaflow model
thanks

 

A little - Save yourself some doe and just get the muffler. If your into mandrel bent or want it semi quiet , just dump it behind the exhaust.

It will still be quiet , if that's what you want and you'll have max gains that way.

It depends more on the Magnaflow muffler type you get as far as how loud it is..