Nick, NXI reckons £1,500 for top condition ones as per this post in which I said I may sell my second set and get some BBS LMs. Daniel on here wants some and HSC911 is also interested.
What are you going to replace them with? Are they your spare set or the only set. Apologies I will reply to your last, just been busy.
I would not sell them if I were you... It took me 12mths to find a sensibly priced set of 996.1 GT3 wheels. At the same time in Germany they are EUR1500+ and EUR2k for 996.2 wheels.