Bilstein quotes $175 per shock for a standard service of a PSS9.
Service
Additional parts required for replacing the bent shock would be extra but the last time I called about replacement parts for a PSS9, Bilstein was not interested in selling them or splitting up a new kit to sell an entire new strut. I have heard of a few that were persistent enough to get a different answer but the price they paid for a single shock make it a less then attractive deal.
If you shop around, new Boxster PSS9 kits are advertised at around $2000, which makes pursuing the rebuild option less attractive which I suspect is part of Bilstein's pricing strategy.
As always, if your interested, make an offer. Additional photos are available on request.