I was thinking about an 18" Magnaflow Single in duel out and having the exhaust exit behind the rear wheels on the same side as the stock exhaust. Are there any performance gains from having a Single in and duel out vs. the single in and out? Because I have the 35.7 gallon gas tank, I think having the pipes exit the rear would be problematic. Not much room in front of the axel.

 

you can get them straight out the back no problem, the shop can do all that for you. as far as performance, some say that SISO is better for torque.

 

I don’t want to loose any torque. I guess I could go with a single in and out and put a duel tip on it. I just need to decide on muffler length. What is the OD on the stock pipes before the muffler? 3”

 

stock pipes are all 2.5" i believe.

 

No performance difference between SISO & SIDO. If there is it's minimal. Only place I would not exit the exhaust is the drivers side in front of the tire, that's where the gas tank is. So go with whatever you like. 14" or 18" sounds awesome.