swansea scooby doo

Hi, I need to sell my cool grey 1999 (v reg) WRX STI version 5 but am not sure what to ask for it. Mot until feb 2006,tax until end may 2005. It's in very good condition and standard apart from 17" bk eclipse alloys and a hks raider exhaust. It's done 54 300k miles. Been serviced at DRJ in Carmarthen (paperwork provided) and only run on Optimax and nitrox booster. It comes with aircon,tracker,snooper n6, cobra full closure alarm, immobiliser,cd player.
I have had it in auto trader for £10,300 ono but with no interest which makes me feel this may be too high.
Any sugested realistic prices would be appreciated.
Thanks
Tony