I think that is correct, it is the pillowball uppermount. Tein describe the CS as having 'A hard rubber upper mount is used for noise proofing' and as the Flex doesn't have this.......
Indeed full leather is not the best choice however europeans seem to have an obsession with it and therefore it is much easier to sell you car if you have it.
Bridestone has new runflats - were they them?
If they are like the ones fitted to the SC430 then there are not worth it - their ride quality is very poor.
I did get a price from Chris last year. Over £300 each and I'm not sure if that is with centre caps (which are £33 each).
There are 3 on ebay at the moment (no centre caps) - I have 6 of them so I can let one go but I haven't tested if any of those are buckled.