Outdated Duramax Diesel Engine Addon for D-Series/H-Series/Roamer/Grand Marshal/Hopper/Burnside 0.2.4

Hey mod-users! Been quite busy, but was able to make this happen.

What's New:
- Added 4 inch and 5 inch Straight-pipe Exhaust options w/ Sounds
- Added Support for Roamer (SUV) and H-Series (Van)
- Tweaked all Tunes and added Smoke Tune
- Fixed transmission/transfer case issues
- Smoothed out all the tunes
- Added Custom Model to Stage 3 Twin Turbochargers (Huge thanks to @iRetr0x ) Seriously cannot thank him enough.
- Fixed Engines randomly blowing up with Stock Tune
- Download it to see everything!