I have come from a 40d SE with dynamic pack (including sports suspension similar to M Sport cars in the UK) and 20" wheels with Brigstone run flat tyres. The ride was poor and I was sorry that I didn't choose the no cost option of deleting the sport suspension. I do like the look of the 20" wheels as well.
My F15 M50d has adaptive dynamic suspension and 20" wheels with Pirelli run flat tyres and is much more comfortable and softer over bumps. I don't know how much more comfortable it is compared to a similar car without adaptive dynamic suspension but the active anti roll system is fantastic so I'm very happy - particularly as I didn't have the opportunity to drive the combination I wanted before ordering it.
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