Depends on a lot of things.. I have seen a silver set of 4 sell for sub $1k on ebay (without tyres), so if you are in a rush to sell, you might be looking at a figure like this.. If you can afford to wait, you might get more. It really just depends on how much someone wants them.. and how much they are willing to pay.
I tend agree with n15m0, the fact they are black, may cut down your customer base quite a bit.