Get an engineer to look at it and give a survey. Will prob cost in the region of £300 to £400 but could be worth its weight in gold if there are problems with the aircraft.
I have seen a Ralleye that looked in fair nick from the outside that needed a top overhaul and had extensive corrosion problems internally, which left the owner with two big bills in the space of a year, which going back 10 years ago cost him in the region of £5000 (plus annual check costs!). He hadn't had it surveyed. TBO as set by Continental is 1800hr or 12 years.