I have a GM compressor on my SD. There are others who are using GM compressors with no problems. They're certainly cheaper, and they do the job correctly.
-Joe

__________________
'81 MB 300SD, '82 MB 300D Turbo (sold/RIP), '04 Lincoln Town Car Ultimate

Sooner or later every car falls apart, ours does it later!
-German Narrator in a MB Promotion Film about the then brand new W123.