Originally Posted by Rossifumi
M Performance springs are red.
I don't think it will be that much firmer, I would go back to BMW and say that you want the extra 10mm drop.
If this kit's springs are like the other BMW models M Perf kit, then the springs rates are a good bit firmer and should be quite noticeable.
I believe the rate increase is like 48% firmer than the standard suspension and 34% firmer than the sport suspension, that's a good bit firmer. Plus, as you note, they lower the car by 10mm lower than the sport suspension.
I'd like to try those springs with my adaptive dampers.