help buying a porsche

hey i need help i found a porsche that i wana buy but i want to make shur its guna be a good buy i'll describe it
 
1987 944 s 5 speed with 141,000 miles on it but other than high mileage the car seems mint
 
iv never baught a car like this so i need some help so i dont end up buying a pain in the ass
if u guys need some more info on the car just ask and ill try to answer it
 
                                ANY HELP WOULD BE GREAT!!!!!!!!!!!!!!!!