bit of advice

hi guys im having a bit of a dilema at the moment as i cant decide wether to keep my mk1 zs 180 or sell up the plus points are its fast,looks good,handles brilliant,very comfy interior,huge boot space,
minus points are general running costs,£300+ pound monthly fuel bills
so if i was to sell up wot do you think would be a realistic asking price for a 2002 52 plate mg zs 180 saloon in british racing green 47000 miles on the clock colour coded half lth monaco seats uprated cd player,electric fnt windows,electric mirrors,aircon,uprated lenso rs5 black alloys 7.5x18",and a janspeed xpower back box