What year/price range are you looking at?
All 2007.5+ Cummins have an exhaust brake.
There are slight differences over the years that will yield better longevity from a DPF., fuel mileage, etc.
Are you looking at a specific brand?
The tuning is probably optional, but I wouldn't tow heavy without an exhaust brake and certainly not in the mountains.
eHoefler wrote:
EFI tuner is for gasoline engines.
Not true. EFI live has been around for quite some time for the duramax crowd and several years for some of the Cummins years.
