With the transmission mount at least, a shorter one still gives you room to add a shim to align the driveshaft/flex disc to the output shaft. Whatever mount you buy, you will likely have to check this, and has been previously posted, some of the replacement ones seem to be way off (too tall) for the drive shaft/flex disc/transmission output shaft to be aligned successfully on a 280SL. Maybe the sellers could/should provide mount dimensions?
Regards,
Ben , Adelaide, Australia, 69/70 280SL, 906G, 904G