watson14

should i run 4 or 5 in
and who makes a better exhuast mangnflo or mbrp

rip 112

4" is suffecient for your truck. 5" will be more a tone change aspect and you can lose some power, not much though. And as far as name brands go they are all good, you can even look at Silverline, Flo-pro, etc.

bighornram

5" has absolutely no performance benefit other than sound unless your running A LOT of power. It does have a deeper and IMO nicer tone however will drone slightly more not to mention cost a little more. For what its worth though i am quite happy with my Magnaflow 5" system.

alMout

My thought is pipe is pipe, no matter who makes it. The only real difference between kits is the supplied muffler. I don't think you will go wrong with any of the major brands.
I recently installed a 4" Silverline exhaust and am quite pleased with it. Very good buy for the money. It replaced my stock pipes and 40" Donaldson muffler setup. The Silverline sounds so much better, a nice deep tone and just a little louder. Gone is the "mechanical whoosh" sound the prior made.

tritont

you may want to look at Hushpower. They have a whole new technology of muffling and will add to the hp if anything. I was told after some dynoing up to 13hp/30tq was seen.