Now guys don't get me wrong, I absolutely love my XM. But my 2009 750Li I traded in on it was rated at 400hp and everyone that I know especially my wife which has had the most pilot time of both vehicles say my 750 was faster! No facts to back this theory up but in my opinion it should not even be a question. Mine is awesome but in no way feels like 550hp. Maybe my expectations were a little high for 100k and 550hp?