I’m starting to think this is more trouble than its worth. By the VDS Z4 do you mean #SC-7059? And what’s the Japanese car? The Scale Auto website does not list any R4 chassis on Z4s. The #SC-7059 is listed with a SC-8000 R2 chassis. 132SlotCar.us doesn’t say crap about the chassis, although they do list numbers for chassis parts.