We've had great success with the Bullydog products too. Nice thing about the Bullydog set up, is that it is updatable and has a USB connection for upgrades aswell. I'd have to say the cummins motors pick up a little bit more than the Duramax/Powerstroke trucks. It's not uncommon that most of the 3/4 ton trucks we do, see well over 23 MPG on the freeway. Not to mention have 700+ FTLBS on tap. Edge has been nice, but the Bullydog is an easier set up, and if you have a problem we can link directly to Bullydog. Another thing you may want to think about doing is deffinately an intake, and eventually a nice turbo back exhaust. Not only will your EGT's go down, but you can crank up the settings when you're towing. On the Bullydog's you don't want to step up over the performance setting when towing with a stock exhaust/Intake because your Pyrometer/EGT will go through the roof.