Water pump OEM BMW or Pierburg

I'm working on adapting these water pumps to a variety of older engines. This one will be going on a Chevy LSx. The pumps support two different control schemes; one via PWM (no feedback) and one via LIN. I will be working on reversing the LIN communications and building a more sophisticated controller soon.

PIERBURG makes a good water pump...

Well made, but they ain't cheap. Here's the diagrams for the N54 setup: http://www.realoem.com/bmw/par...fg=35 The water pump itself is over $500.