It isn't defaulting to M2 in manual mode. If you stop in Park, and then shift to drive, and then move to DS, it will be in M1. The reason it 'appears' to default to M2 in DS is because of the shifting logic. It only 'downshifts' to a lower gear when speed and RPM require it...that's why you can't stop in M5 or M6. So as you slow down from speed, it shifts down to M5, M4, M3, M2, and then stops. The car is capable of starting from a stop in M2 (which is ostensibly useful for slippery conditions), so it doesn't 'require' a downshift to M1.