Hi mako! Sorry man, I think everyone is just trying to prepare you for a few hefty-ish repair bills just in case. It seems most have had to pay a few grand up front on an older Boxster to get it up to snuff. My daily driver '99 was bought with 124,000 miles and no records or history whatsoever. I paid $4500 for the car, plus $6,000 in repairs and maintenance over a few months because there's no such thing as a $4500 Boxster. However, since that money was spent, the car has been one of the most solid, reliable, crazy fun cars I've ever owned for a $10,500 investment. And I drive the absolute &@#% out of it every day.
You're starting in a much better place with 78,000 miles and the other perks the dealer is offering, and $6500 is a good price for the car!
However, there's no such thing as a $6500 Boxster either, so you'll have to go in expecting it will need at least a few little things. It's just something to keep in mind, that's all.