Bullshlt or not judge for yourselves. Spoke to a friend of a friend who works as the service head at a BMW dealership about a remap of my 523i.
1. He claims the difference in power between 523i and 528i is pure software.
2. On the E60 a remap would be found out if actively investigated by the dealer or BMW. In the course of a normal service the dealer wouldn't see it.
3. On the F10 if there has been a remap performed once the car is connected to the computers for service the evidence of the remap will show up immediately at the BMW Batman Cave in Munich even if the dealer doesn't see it.
To me no. 3 sounds like a BS rumor spread by BMW to scare people away from tampering with their cars but hey, who knows?