My 2 engines, an M30B34 Euro and an M106 Turbo both have the viscous fan clutch and are compatible with the modern black fan. The SEM paint I called out is for flexible surfaces and formulated for something that flexes like a plastic fan blade. I've run Sahara, the 72, for approximately 6 years with no degrading of the paint or color and Sixto, the 74, has had one installed for 2+ years. My major concern is how well the fans cool the radiator and to me a more modern fan that looks period correct in motion trumps having one that pushes less air and has a higher failure rate. I drive both Coupes a lot on back roads and freeways and want to eliminate the chance of a failure, especially with passengers.
Regards, Jon