[TransAmx2]

If it were me personally and I was dealing with a reputable shop I'd let them do the tune and even install headers if you want. In my experience a reputable shop will honor their work and work with a reputable manufacturer to make things right with a customer if something goes wrong.

If something goes wrong because of the tune or install I would expect the shop to take responsibility and make things right. If something goes wrong because of a manufacturer defect I would expect the shop would work with the manufacturer to prove it was a manufacturer defect and expect them to resolve it between them, whether using a caned tune or not.