My final word on this is that you have to sit down, take a breath and realize that this is a luxury buy. You do not absolutely need it, nor do you need it TODAY!
Look at other '97's, with higher mileage. Take the difference in price and divide that by the difference in miles - that'll be how much you're paying for the 'unused' miles.
While it's true people over-value their cars, it's the best negotiator who wins in the end. Think about how long it took you to earn this money (or how hard you'll have to work to pay the loan) and negotiate from that basis. You have something the seller wants - money. The seller has something you want, but he's not the only source of satisfying your desire. The buyer has the edge. Sure the seller can refuse, so what? You just have to find another one and as far as the Boxster is concerned, there's no shortage of them.
In the end, you have to do what you think is best. No one here can tell you what to do. It's good you're seeking advice, but in the end, you have to intepret this advice and act as you see fit. Good luck!
