I had been looking for OEM esque rubber floormats for my E30 and after years of searching have come across something that truly looks OEM, and is OEM (except that these are made for an E82 by BMW).
OEM BMW part number:
Black – 51472239697
Grey – 51470439165
Beige – 51470439166
The best part is that they are only $40-50 from the dealer/online and are usually in stock at most dealerships.