Wow! Sounds like fun! Did your friend ever go through with the 6.0 rebuild? If I were doing such a thing to the 500E I might go for the Brabus 6.5 V8. Even in stock form the brakes are the least impressive characteristic about the car. Car handles great given good tires, goes like a raped ape (even in 5 liter form), but the brakes are not proportionally better (as everything else is) than the 400E brakes in my experience. All things considered the brakes are the least impoved over its lesser W124 siblings. Still a helluva car any way you slice it.

Keep in touch...Lee