Originally Posted by Uncle Bulgaria
I live in South West London, where the road surface is full of holes and speedbumps.
Over the last ten years, I've regretted buying an E46 MSport touring (and an E55) purely because of the way they thump and bump over the roads locally. Take them down to the nearest Nurburgring and go round bends at 100mph, and there's no better choice. But on my normal weekend they were just a pain in the back.
Over the same time I've had two E39 SE Tourings, an S500, and my current 325i SE, and they've all been comfortable at low and high speed. I don't do The Ring, so logically I don't need "Sport" suspension. "Normal" settings should be fine.
I have also had SE and Sport E39s and E46's and on those cars the SE is softer, however, in the case of the E9X cars the M-Sport soaks up rough roads and speed bumps better than the SE, as long as it is on the same wheels.
We tested this to death about 3 years ago.
Take our a 318d or 320d on the standard 17" sport wheels to see what I mean.