Check with Dougherty Automotive in West Chester, Pa. They are a Fikse dealer and seem to have some fairly decent pricing. This is a professional Porsche race shop. Visiting it alone is worth the trip. Millions of $$$ of machinery in there in some state of modification or other. This is where I got my Fikse FM-5's from.
To me, the FM-5's are the wheel that should have been on the C4 from the General. The look is verry impressive.
Check
www.fikse.com. They have a modeling center there and last time I was there they had a couple C4 Vettes with those wheels.