Do all the obvious things like check for accident history, money owing, cosmetic and mechanical condition. Educate yourself with known issues with the car such as DI seals, rough idle etc. and have a good look at maintenance history. You should more importantly assess the owner themselves and see what kind of a person they are because you can tell alot from how the car has been taken care of from that. Do they sound knowledgeable and know what they're doing? Do they granny shift or are they double clutching like they should
. Let them drive the car to see how its been driven. Also you must drive at least one other 86 to have something to compare it to, it'll give you a really good indication on what's normal what's not
Really the car is still pretty new so most of the information you'll get on its condition is the owner assessment