I dunno. Even though the UK is not nearly so litigation happy as the US, it seems to me that there would be a lot of liability in producing a product which, if it were to fail, could cause serious property loss and potential injury and death. Especially one for high-end Sports cars and most likely, equally high-end owners.
I'm no expert in the manufacture and implementation of CF, but I do know that you can engineer it to perform in a certain way and can engineer it's strength. There are CF composite commercial aircraft wings out there with a built-in deflection of 2 or more feet which perform flawlessly cycle after cycle.
CF wheels are not really new. There are several manufacturers producing them for Bicycles and Motorcycles, and have for quite a few years. I realize the stresses imposed by a bike are far less than a car, but that's where the engineering of the material comes into play. See:
http://www.ram.mc/wheels/BST/techinfo/BSTekinfo.htm . And another company, DYMAG/Rennworx, won Best Int'l Product award at the 2006 SEMA show for their CF Wheels -
http://www.prnewswire.com/cgi-bin/stories.pl?ACCT=109&STORY=/www/story/03-15-2007/0004547117&EDATE= .
I am certain that there was a lot of destructive testing conducted before these wheels were marketed, or gained TUV approval (Technischer Überwachungs-Verein), which I doubt was just a rubber-stamping procedure. The TUV is one if the strictest independent testing organizations in the world (similar to the UL (Underwriters Laboratories) in the US). Every Car and Aftermarket part in Germany must, by Law, be TUV approved in order to be licensed for the road. So, my confidence level is fairly high that this wheel performs as advertised. I mean it has a greater approval (Full TUV - meaning on and off road) than many of the wheels many of us are riding around on now.
Now, all of this comes at a price, which helps explain why they cost so much. But, if the claims turn out to be correct, they may not be so expensive afterall.
A promise of the equivalent of 40 bhp is nothing to sneeze at and their cost somewhat comparable to the price of a 3.4l or 3.6l conversion while adding the benefits of better turn-in and increased Range (MPG), but without any reliability issues from Forced Induction or overpowering the drivetrain.
Of course, this is just the first example of a CF road wheel available for Porsches. I'm sure there will be others, and that with time, the price may fall to a more reasonable level.