dealer does not offer SAS separately just in a steering column assembly. purchased SAS used unit on e-bay and shortly after installation the same code(C1140) reappeared. local mechanic who read the code stated that he had some bad experiences with aftermarket parts in these type vehicles and would recommend dealer only parts. researched online yesterday and found a SAS unit manufactured by a reputable German firm. can anyone shed some advise about this approach? an entire MB replacement steering column is a lot to consider versus a quality SAS unit. thank you!!