Hey man I'm about to take my car in for this. At my local german auto shop, they say this is typically the accessory belt tensioner going bad. Under pressure if loose the steering will shudder - like when manuvering out of a parking spot. This belt tensioner may be called something else, though it is the one for the steering for sure.
I'll update if I get it corrected. PB
BMW Performance Suspension, Lowering Perches, Cobb AP, Beyern Mesh 18" 265/235, Golf Tee, Tint 20%, M-Tech Front/Rear [b][i]