I made a post a very long time ago about SMC Solenoids as they are somewhat hard to find:
http://www.chiefdelphi.com/forums/sh...763#post908763
Adam Heard put up a whitepaper here (pretty darn helpful):
http://www.chiefdelphi.com/media/papers/2414
I would buy from Motion Industries or Pneuaire, Motion has been the fastest for us.
-RC