Your review and elgyqc's summary are great.
Questions:
What does your wife think about that car? You can drive it pretty much as-is, but it is going to take either a lot of time or a lot of money to make it as nice as a $12K car. Is she going to be on board with that? Will she be okay with it as-is for a while?
The start up noise; Is it a squeal from the starter (starter lube/rebuild)? Electric motor sound like a vacuum cleaner (SAI blower)? Tapping/rattle sound (could be acceptable or a major concern)?
Before paying for a PPI (if you are serious about the car) can you remove the oil filter and get a look for dirt/debris? It can be unscrewed with a tool and examined without draining the oil. *See the 101 Projects book or this article:
https://www.pelicanparts.com/techarticles/Boxster_Tech/02-BASICS-Oil_Change/02-BASICS-Oil_Change.htm
The front bumper and frunk lid may be simply installed poorly or it could have had an accident. I'd want a better look at that or detail it in the PPI.
Me? I would make a low cash offer and throw some parts at it that I already have on the shelf. If I wanted some cash back from it, I'd sell the Litronic headlights and put a used set of Halogens in and delete the headlight washers. The headlight washers on most of these cars I've seen are like that or have already been replaced. Bad design.