Not sure what some of you guys are talking with the no performance gains...I threw a single exit Magnaflow catback on and immediatley noticed a nice difference in performace and sound on my 05' 5.4 Supercrew. I had a lot quicker acceleration. I have heard and read where a dual exit exhaust can actually loose a little power, as opposed to a single exhaust. I also added an Airaid intake with it later, and damn, its very nice. Now I couldnt resist, and have a XCal 2 from Troyer on the way.

https://www.f150online.com/galleries....cfm?gnum=6172

 

Yeah, I was worried that would happen with a dual exit exhaust, how big are your pipes (my SIDO are 2.5"). If I were to recommend an exhaust I would definitely recommend trying out the SISO magnaflow as I do not realize ANY improvement, and possibly very slight low end performance decrease if anything. Not sure though, right now my truck is pretty quick after intake and e-fans.

 

I installed my Magnaflow SISO 3" to a 4" Tip Weds and I have to join the club and say thank you for all the people giving there opinions on this forum. I couldnt be happier with my new exhaust. There was a noticable difference in the way the truck feels. I know there was no low end loss but a increase. Dont get me wrong still needs a tuner to make it better. Ford shift points suck. But I really am happy with the choice.