As long as the seller has no issues with a PPI to be performed you should be the one calling the shop and making the request . You tell them you are thinking about purchasing the vehicle and you want a bill of health . You want to know the good and the bad if there is any . In a perfect world it's the same shop that has performed service work in the past so they can tell you about anything replaced/repaired in the past .
The quality of the PPI is obviously an extension of the quality of the shop . If the shop doesn't know all the ins and outs of the particular chassis/engine then they may not be much help . Any shop can tell you about brakes/suspension but can they detect bore scoring ? Many can't . Good luck and report back .
