Actually--again on my former E-24--I ran with bilistiens and changed out the McPs (on the front) to try to improve the situation.

High speed cornering on my current E-24/M is pretty good, but I probably outweigh your brother's M by several hundred pounds.

I just see people changing out the SLS at with a minor snafu under the guise of "an upgrade"--I don't think it is.

Uhh, MacPherson Struts go on the front of the car, not the rear. They have nothing to do with the rear self-levelling.

How was removing the SLS a big mistake? Did the ride quality suffer? If so, then this is the fault of the Bilsteins, which are notoriously harsh. Great for smooth, high-speed tracks, but bad for regular roads, especially in US cities.

The M-Technic springs and properly valved Bilsteins are a great setup. Better yet would be properly valved adjustable Konis or other high-performance shock.

My brother's M5 still has the original SLS rear which works great. Problem is the handling sucks during high-speed corner entry!

JamesM

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I am a fan the interactive (self-leveling) suspension. I have in one of my previous 6 -coupes changed to bilstein--biggest mistake of the car's life it hoovered.

And don't even think about mcpherson strutts--been there done that.