Originally Posted by mikewills
^^Cool. Can manufacturers determine if the stock ECU tune was compromised, even after re-flashing back to stock. Perhaps a flag or trigger that users or tuners can't see.
Yes BMW can tell if you had a tune. They may over look it but if you have a problem that they can relate back to the tune your warranty is done.
Intakes and exhausts are ok from what I have been told but I'd still get that in writing from the dealer just to be extra careful.