I just bought the audi pump 8K0965567 which is the CWA50 off a used car on ebay for $120. I have the wiring figured out as there is a great thread on the MB World forum with all the info. Thanks for your help. I also have the four prong connecter coming from FCPEuro if I need it.
Thing is the CWA100 draws twice the amps and that is what really had me concerned.