Could anyone recommend the best exhaust setup for an 07 f150 xlt with the 4.6L I was thinking a flowmaster si/so with 3" pipe out for 150 at my friends muffler shop. is changing the diameter of the tailpipe too much or is it okay don't want to lose too much bottom end.

 

3" out wont affect your performance, only the exhaust note. ive got a fm si/so 40series dumped (2 1/2") and it sounds nice. hope this helps

 

3" on a SISO will be fine. I'd suggest Magnaflow for better performance.

 

a Flowmaster 40 would sound nice. I'd actually like to recomment the Dynomax Bullet muffler for you though, because they sound great on 4.6Ls, and are very affordable ( $40 some ) or a Magnafow more possible performance gains.

 

Another vote here for the Magnaflow......