I've read about this guy for a LONG TIME! Been around for quite a while but the tune doesn't deliver nearly what the seller claims it will...probably why the product has been around since 2008 and NO ONE HERE EVER DISCUSSES IT
TECHNICALLY, the duramilage tune is Very similar to a "stock trans" safe EFI tune, heck, the guy could be using EFI to tune... I remember the Duramilage tuning has a 65, 80 and a 100hp tune...?
YOU WILL NOT SEE A 4-7MPG INCREASE with this tuner or ANY tuner, using the same driving characteristics...ANYONE claiming to gain 4-7mpg with a tune is breathing their own exhaust
You WILL see about 1-3mpg increase with just about ANY decent tune, finding a decent tune is your job...some are better than most, most are not that great..
Honestly, I don't think it'd be all that bad, but personally, I wouldn't use a tune on my truck that wasn't crafted by one of the vendors here...
.02¢