I just saw an "83" ///M635csi buried in the back lot of a local GM dealer. The emblem on the rear deck says ///M635csi What are the distinguishing features of the ///M engine so I can tell if this is a genuine ///M or not? Anyone have a link to an engine photo? The dealer is closed today, but they have a price of $4800 on the windshield. The body looks great, the dash is cracked above the instrument panel.... do not know anything more until Monday when the dealer opens. I own an ///M Roadster, but know nothing about the 635's. Any help on what to look for on the 635's will be greatly appreciated.