I've seen the steering wheels for S3/4 aero's on Ebay, they appear to be German made and the same as fitted to the Aston. The Max wheels are Japanese (Ray's Wheels), and the pattern is available to purchase in the US, but not in a 19 inch fitment when I was originally looking. The S2/early S3 wheels were supplied by Rimstock but made somewhere in Russia (or one of the satelite states).
From memory, the window mechanism of the Maclaren F1 comes from a Citroen Saxo!
Brake pads for Aero's are as fitted on Lotus Elise