[Quickurt]

It's pretty safe to say any modern engine should go 200k miles, as long as it is properly maintained. Many go well over 300k miles. Christophorus just had an article about a 911 in Europe that has gone 350k miles, with the original engine/trans.
Boxsters do have their share of catastrophic failures, but most seem to happen fairly early, before 60k miles, so...............
The problem, of course, with buying any used car is you can never be completely sure how it has been maintained and treated, so there is always that crap-shoot in there, as small as it probably is with a Boxster class car.
Good luck, and look to see you coming on and telling us all about it!!
Do your due dilligence and read all the threads on catastrophic failures and probabaly talk to Jake Raby about years and models to avoid.
I came on here and trolled for over a year before I bought, and it may have saved me a great deal of money.
I know for sure it helped me narrow down the list of what I wanted.