Slanted Exhaust Stack Ideas.....

Ive been looking around and saw a few pictures of HMMMVW's with the slanted stack on the driver side, anyone have any suggestions on a 2 to 1 exhaust conversion for an m1009? I'm don't know much about diesel's would there a back pressure issue if I don't change exhaust diameter? similar to the one seen here. Any thoughts or suggestions....also plan on a snorkel. not sure if intake diameter would effect exhaust either, but I'm smart enough to ask.

yeah something like that.

I'm working on doing this to mine and would also like to know if it will hurt my power, not that I have much now.