...Their tunes are EPA compliant, but the GM ECM's show when the tune has been over-written and swapped in and out, so there may be warranty implications for sure.
I know for fact GM will check the ECM for changes done to it, GM somehow can tell it was changed (GM says there is a fingerprint written evrytime the ECM is updated, or restored), as well as non-GM approved exhausts (Cat back is ok, cat or before is not). GM started checking around the LLY and later diesels (Might have been LB7). GM will deny power train warranty work, and GM will red flag the VIN in GMVIS.
Every aftremarket product in the world will tell you to fight it under the Magnuson Moss Warranty Act, but GM has a few buildings full of lawyers. Notice how the aftermarket folks won't cover any of the legal fees or court costs, that should tell you something. I had an employee do it to a truck years ago, had an issue with the EGR valve. Get a call from the Dealer stating the repair would noyt be covered as the ECM had been modified. I had zero idea what he was talking about, called employee, employee said he heard programmers would make it run better.
Once the VIN is red flagged, good luck when you trade it, if itr's at a GM dealer, some will look in GMVIS to see what the history is, see tha red flag, and will tell you they either won't take it on trade, or will give you pennies on the dollar from what the trade would normally get.
greendieselengineering.com
