first of all, i doubt the kms is right as it is a 9 yr old car. Try lookin at the odometer on the dash board. Are the dials all straight? If not, that means the dials have been fiddled with and clicked back.
I guess an R33 GTST S2 in good nick will cost you about 18-20k depending on the mods the car has as well. This car with recaro seats and exhaust system might be about 21-22k i reckon? Good luck!