I got a '99 last year with 17k miles. I only had one small problem from the car sitting so long, but it was an easy fix. I had a vacuum leak from some crystalized gas.
The only other problems with cars that sit for a long time is that the seals tend to dry out, which may signal an RMS seal replacement (about $600), but that depends on whether or not the car was properly maintained. I would look into an extended warranty mine was 3 years/36k miles for about $3K. It is a nice safety net against expensive problems.
Pre-'01 Boxster's rarely have IMS failure, but they can have RMS failure. So with a newer car you have to worry about both, and IMS can't be detected ahead of time. (RMS can be spotted ahead of time if you catch the oil leak.)
I would say go for it if the PPI goes okay, but just remember all the regular maintenance and parts are going to be about 3-4 times more than a regular car. And I would also have about $2k in reserve for any problems if you don't get an extended warranty.
Hope this Helps!
