I test drove a X6 50i before I getting my X5M just to see how powerful the 50i felt. I thought it was still underpowered and felt lethargic under 3k rpm. There's definitely a lag before the power really kicks at around 3k+ rpm on the 50i. The M is better than the 50i in every way except maybe exhaust sound.

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2022 X5M Comp Dravit Grey/Full Silverstone
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2018 M5 Black/Full Silverstone
2015 X5M Donington Grey/Full Silverstone
2010 X5M Space Grey/Full Silverstone
2003 4.6is Silver/Black