I don't really know too much about diesel exhausts, so these may be dumb questions, but here it goes...Which kind of exhaust is the best for performance/sound on a 2010 F-250 PSD; cat back, down pipe back, turbo back? And also, which diameter(s) seems to be the best for performance/sound? I like the low deep rumble and turbo whistle. I'll also be doing a Spartan Tuner if that matters. Any and all info on this subject would help me out honestly haha.