Bump since I am having some kind of problem similar to this...sounds like the shaking/shudder/slipping is coming from the rear of the car. Any more info on that? I plan on doing a diff fluid change real soon so I'll check mine driveshaft out for anything abnormal.
Mathpro - what was the shops name that you went to? I'm in the loop so I went to RN Bavarian Motors once for diagnostics for speed sensors...
'00 528i Sport, Premium, NAV, Depo headlights, M-style bumpers and mirrors, KW2 coilovers, Eisenmann Exhaust with resonator delete, 19-inch Axis Milano's (staggered), 2 12" Infinti subs, Power Slot rotors, and a trunk full of Dynamat.