Originally Posted by M54ccibo
Don't know about the 550i, but there certainly was not variability on the E60 M5. I cannot believe that there is yet another difference on the F10 M5. Strange.
Oh - and with the E60 some folks reported a gain of 20HP. I'm definitely not claiming that
I always believed that it was a 1.5hp gain on the E60 M5 with the charcoals removed, but this included a slightly better engine response. Who knows!