Are you saying that 8hp is attributed to M Mode? That's not a significant difference on ONE dyno to claim that the M Mode increases HP. Heat soak? Dyno operator? Could me many things.
I would have RTFM first before posting this...just a suggestion. Most here know what the POWER setting in M Mode does.
I personally think is garbage because it takes a sensitive throttle setting and then it makes it even more sensitive. The throttle setting is a waste.
2015 F34 328iX GT Glacier Silver
2011 E90 M3 Monte Carlo Blue
2004 E46 M3 Imola Red