Used it for a few years on my 2007 5.9 and on my 2006 5.9 Cummins trucks. It is returned to stock and ready to tune to a different truck. I just sold my 2007 and don't want to tune the 2006 as its just a work truck now. Never an issue with the tuner, I swapped from tow to performance many times no issues only takes a few minutes unlike others where it takes 30 mins or more. I like this tuner the best out of the several I have owned over the years.