For a 19x8.5, I wouldn't consider anything less than 42mm up front. Pete's posted several times on his experience with rubbing with his Fondmetals. I believe had had to go to a lower profile tire in the front to compensate. Granted, he's lowered a little bit more than the Eibach group, but I thought his issues were more with rubbing on the inner part of the fender well.
I posted a wheel in a different thread that I'm going to pull the trigger on if one of my guitars ends up selling (previous wheel mad money went bye-bye to replace our hot water heater a few weeks ago). It's a 19x8.5 with a 48mm offset. I might be crazy in trying to run a 255/35/19 tire with them, but I think I'll be ok (normal would be a 245/35/19).