I'm sure you've checked the car out properly but make sure it is actually an R27 F1! I saw 2 or 3 advertised that stated they were F1s - they had the anthracite alloys, recaro seats but no stickers, F1 plaque or extra rear tinted windows!! Someone will fall for it even though it sounds obvious to the trained eye!
So be careful as it is pretty easy to full in love with a car but find out it's not the real deal once you've paid