^ Exactly this.
A car is worth what someone is willing to pay for it.
With only one Carbon Grey RC-F in the UK, if someone really wants a grey one, they'll have to pay the price.
I still have not come to a decision regarding what to do with my car, but if I come to sell it, I'll be in no rush to enter negotiations. If I can't get the price I want, I'll just keep it.