This doesn't make sense (more) (archive)

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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.

Changed out the MacPherson Strut to what? Sliding pillar? (don't even go there unless your a Morgan owner!) Leading arm? Trailing arm? Wishbone? What? A MacPherson strut front suspension is a type of a suspension that has the characteristics of: reasonably low and well controlled roll center; a very tall overall unit; roll angle almost equal to wheel angle; hign braking forces are reacted by trying to break the unit and two and tends to lock its ability to slide in/out (but this is if you're pulling crazy g's, not for street cars on road or track); and inexpensive and easy to manufactur. BMWs have used MacPherson strut type front suspension for years! (Exceptions include M1, Isetta, etc.) Other manufacturers use it, and it's become the bread and butter of front ends for a generation now. There was a huge uproar in the press when Honda went to MacPherson struts in the front from double A-arm (or double wishbones) due to packaging issues. The press loved Honda's double A-arm front ends.

Bilsteins, Boges, Konis, etc. are actually supposed to be called "dampers," since "shock" or "shock absorber" is technically incorrect. I could go into reasons why, but basically the definition of a damper is to dampen a force, and what a "damper" actually does is dampen the oscillations of the springing medium (coil spring, leaf spring, etc) in a suspension.

If you've somehow managed to fit in double wishbone suspension in the front of an E24, let's hear it! Otherwise, please avoid mixing up terms.

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.

Sometimes it's cheaper to repair SLS. Sometimes it's cheaper to go to standard springs/shocks. Depending on the condition of the system and what you (the individual owner) are looking for, you should do one or the other. And yes, if you're looking for better handling thru higher spring rates, etc., then it's an UPGRADE to remove the SLS.

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.

What James says here is true. Bilsteins, even in their HD form, are "harsher" than the Boges. But they tend to give more control.

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.

This is a great set-up for those wanting a better performing car, while retaining ride comfort. If you (a) need to use the car daily, (b) family uses it, (c) care about ride comfort, and/or (d) live in the Pot-hole capital of the free-world, aka New Jersey, then M-technic offers the best solution/compromise between real world issues and your desire for better handling. Again, what James said is spot on.

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

Another thing you have to remember is how the M5 was set-up originally from the factory (in US form). It understeers. James found how this exact behavior manifests itself. Also, yes, it can be pushed into oversteer generally in one of two ways by (a) power, or (b) lift throttle oversteer, since trailing arm rear suspensions have that tendency.

One of the reasons you cite for poor corner entry has to do with the camber gain of the front versus the rear of the car. The rear suspension gains a lot of camber when in bump - something you're looking for when cornering to keep the tire flat on the ground and get the grip. However the front doesn't gain all that much camber during bump. In fact, it's pretty damn bad. I've driven my car stock and found this exact problem. You want to install camber correction mounts, or adjustable camber mounts on the front and lower your front end to gain the most negative camber, so that you're not endlessly pushing in the front. (and whilst doing this, you can add lower control arm spacers like Ed Walters to get even more camber gain during bump.) Take a look at the cornering picts of stock E28s in magazines and you can see how the rear tire is practically flat, whereas the front tire is leaning way over into positive camber territory.

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