Many of Bob G's parts are sold under the VPD label. You're better off dealing with Bob directly. Most likely you'll get Bilstein's in his suspension kit as QA1 dropped the GP series dampers when they purchased Carrera. Just be forewarned that Bob's stuff is functional, not beautiful.

iPd sells a few parts here an there. Although they raced 142's back in the day you'll be hard pressed to find a "race" part in any of their catalogs.