Hi, I've been trying to find low priced rear brake rotors for my 88 5000CS Turbo Quattro Sedan and came across ThePartsBin listing Zimmerman rotors for only $30 (N1000-20355) or $35 (N1000-20480) each. Never heard of this brand. Anyone know whether they are any good? Any other suggestions, especially where to get used ones? Lou in Vermont