[fastpat]

Using your named guidelines, I'd recommend considering only the Boxster. An "SC" would be problematic since it's likely to have a lot more miles on it.

I will go further and say that if you can swing the difference, I'd go to the $22-25k region of expenditures even if it meant adding a year to the payment schedule. Much nicer, more recent Boxsters can be had at that price point.