I just replaced the water pump on my E30+ 2 weeks back. I'm in the Bay Area and found the Oberdorfer pump in Sea Power in Oakland for about $150.
However, after taking apart the old pump I notice that the pump casing was in great shape. All I really needed was some new seals and a new impeller.
Also you might want to replace the grease cap before it rusts and breaks (which is what happened to me).
dan