What do you guys think about running 3" pipe from the cats back to a 4" turn down or dual 4" cannons? i know it sounds really good but i don't know about performance. would i get more performance from an actual muffler or does it matter? '04 f-150 4wd 5.4

 

if you go with a smaller pipe perhaps a 2.25" or 2.5" rathar than the 3", you will gain performance. the 3" pipe will most likely loose power and sound. and definitely go with an aftermarket muffler- dynomax,magnaflow,spintech,flowmaster

 

go with a single 3'' into a dual out flowmaster for best performance on a stock/mild truck, dual 2.5 for medium and dual 3'' for over 500 rwhp