i always push it on the move, and as much as the car does change its temper as stated above. its nothing like when you push the M button in the E60 M5 and 100+hp hits you.
2016 BMW X5d - Black Sapphire on Terra
2016 Range Rover HSE TD6-White on Ivory
2010 Audi R8 V10 Coupe 6MT-White on Red - gone but not forgotten