Edmunds test reached 0-60 mph (100km = 62 mph) in 7 seconds, not what BMW claims but it could have still not been broken in or could be due to different altitudes / temperature conditions. They also tested a supercharged RR in a different article and had 0-60 of 7.1 seconds. Not too bad considering the X5 has a horsepower disadvantage. I would say if you have to have to quickest SUV around look at the Porsche turbo Cayenne.