I got a price from a couple of professional paint shops and £500 is not a lot off what they wanted. I decided to keep them as they were after a bit because I grew to like them, I also considered powder coating the wheels and left them for the same reason.
I have heard of the warranty issue before, but honestly believe it is bollocks. They may try to convince you it affects your warranty, but the EU ruled against this kind of crap years ago, that is why you can take your Porsche to any dealer with the right equipment and as long as they fit genuine Porsche parts (or parts of at least the same quality) then it is illegal for Porsche not to honour the warranty. To me the bigger issue is that it may hit your resale as many Porsche dealers may knock down your price come trade in time or shun you all together?
James