You are right about those high prices on parts for the CS, maybe that is one of the reasons the selling CS price is so low and not an easy sell to boot!!. Usually I spend hours calling for parts (used/new)they are hard to find and very high in price...ex. needed a shift indicator (new) for my CSA the quoting prices ranged from $175-$382 it took 3 days of calling to get the right part at the right price. Also I install parts from other model BMW's the wiper motor could come from 633/635, Bavaria etc. window wiper squirt motor from 2002 and so on, anyway you are not along on this just have to bite the bullet and drive on.