If you take a look at my build thread you'll see my "exhaust system" - just a slightly curving pipe thru the front fender. Really, no difference yet (I'm adding go-fast parts as I go along). The turbo outlet is only 2.25 so there isn't much to be gained as long as you're running the stock hot-side casting. If you go to a bigger turbo outlet then I'd suggest a bigger pipe.

Along that line - on my Dodge/Cummins, I asked Edge if I should go up in pipe size. They were clear that unless you're north of 500+ HP there's NO advantage in the big pipe - and they sell them! So they talked themselves out of a sale and I appreciate their honesty.

LEAVE THE ALDA!! I pulled mine and I think I lost power - no improvement in top speed (I run Land Speed Racing at the Ohio Mile track) even though I bumped the pump timing and did other stuff that should have helped. I have (but have not yet installed) a Dieselmeken injection pump (it's the "hot" set-up on these) and the pump builder includes ALDAs on his performance pumps. The ALDA adds fuel in proportion to boost, which you want. There are some ALDA adjustments that you will probably want to try but taking fuel away from a Diesel is NOT how to make more power!

Dan