Oak green is one of the overhiped colours, everyone chucks it about saying its rare and desirable but oak green is as common as tornado red in my eyes, there are rarer colours out there!
The other problem you have is the fact that your car is a campaign model but effectively the value has been decreased with the addition of big bumpers and the bbs ra alloys, ok they would appeal to some people out there but most people like me would be put off by this.
Really its a hard one to price as the market for mk2s is a bit all over the place at the minute, at the end of the day if someone is looking for a car that spec they will pay what they want to get it