If you get hedders, full exhaust, AFE PG7 intake (stage 2 if they have it), and a chip, then MAYBE you can get 60 hp at the flywheel (not rear wheel HP) out of the 8.1
There are quite a few guys that run the Aero turbine mufflers on their diesel trucks on TDS or oilburners.net. I'm not going to bother with any muffler or CAT convrter soon anyway. For a diesel, straight pipe is the cheapest way to get your EGT's down. However for a Gasser, straight pipe will hurt bottom end due to the fact that gassers need backpressure. Hope this helps.
Believe none of what you hear and only half of what you see!
Good luck, JON.