A sedan will always be tighter in an older car - the B pillar just gives it more structural rigidity. The doors are going to close better, longer. Coupes can be a pain in the ass in some ways. Window regulators are riveted in rather than bolted. Rear window repair, seat belt presenter repair, etc are a pain in a coupe. For some reason front struts are more expensive. Coupe unique parts are going to be harder to get and sometimes more expensive. On the bright side 124 coupes are shorter, better turning radius, more nimble. They have much better potential for future value appreciation. For the driver they're easier to get in to. Plus they just look a lot better. I think 124 coupes are one of the best looking MBs ever.