I've used many different tuners (A'PEXi, Hypertech, Superchips, Edge) on built 2.2l to 6.6l Duramax and I'm tired of generic big box tunes and the associated problems. I'm currently patiently waiting on an in person tune from Black Bear. Their reputation is flawless, I don't consider the email complainer guy a customer since he didn't buy a tune. Just my opinion