[josec70]

This topic has been beaten to death.

If you flash tune be prepared to pay if something goes wrong, plain and simple .. having a good relationship with your SA is not going to help one bit once BMW NA is involved as the tune is easily detectable. You more than likely will get flagged before you even have a problem.

A friendly SA will look the other way on many mods including a piggy or, at least, that has been my experience. I have had many piggys and have never had an issue or a warranty claim denied.

That does NOT mean it can't happen, just has not happened to me. A piggy will leave recorded data outside of factory parameters but is inferred and BMW will decide your fate based on the data they extract.

Conclusion:

There's a price to play the game ...

Flash tune is headache worth avoiding IMO but I would roll the dice with a piggy .. I would still remove it for service even with a friendly SA as you never know and it takes all of 5 min. My two F10 M5's both had piggys and I never removed them based on my long relationship with my SA. I didn't go with a piggy for my current M5C.