Thanks for the input! I'm not really worried about flying with a
metric ASI since that's what I'm already used to from learning to soar
here in Germany. I think I'd probably have a harder time adjusting to
flying with a Knots ASI, but it wouldn't really be that much of an
adjustment, just have to learn the important speeds again in knots.
I'll talk to the FAA maintenance inspector that I know back home and
see what he knows about the legality of instruments in a sailplane.
The U.S. type certificate for the Phoebus says it must conform to the
German type certificate which states that the glider must have an ASI
and an altimeter, but the limits specified in the orginal German type
certificate are all metric...go figure! Thanks everybody for your help
and maybe I'll get to meet a few people when I get back to the states
and start flying there again...although I don't know exactly where in
the states I'll be going yet.

Adam