[PLF69]

Here is my take driving my M3 on track.

Efficiency mode is not good because it creates artificial delayed power delivery and although it will help some manage there corner exit or shift more smoothly it can be really unsettling when the ecu reaches the point where it gives you all the power.

Sport I found strange, I think it's the best to get used to the car and power dilevery altrough a bit jumpy on the street ends up being pretty smooth on track. Probably the best mode to familiarise yourself with the car.

Sport + is what you want to adapt to on the track but I would never use it on the street cause it's much harder to modulate. On the track you will want all the power anyways without any delays so it's best to adapt yourself at being smooth in the mode that gives you the best response and the full beans.