1. Check the service history. The car should have been serviced every 10k miles, ideally less. Lack of oil changes can lead to oil system related failures, so the money you save initially ends up costing the same or more down the line.
2. Ideally you'd have someone with VCDS (Ross-Tec) check the car for fault codes, as this can quickly reveal any problems the car has, even problems that are serious yet don't create fault lights on the dash.
3. Check for rust on the front arches, between the rear bumper and rear arches, around the badge on the boot. The wrap may have hidden any rust, so look carefully for unevenness in these areas.
4. Ask for proof of the '280bhp', I'm sceptical it's that powerful given the mods the seller has listed.
5. 3" 'Turbo-back' exhaust means no catalytic converter. Unless the seller is selling the original catalytic converter with the car it will not pass an MOT on emissions.