My 2001 Boxster S went 200,000 miles before the engine threw a rod, just installed a used motor with 100k on it... pretty sure with regular maintenance Ill get another 100k out of it. If you can I felt that the S model is worth the extra dollars over the base model. I did a little video on the big differences for both a while back, here is the link:
https://youtu.be/MmEkqvWf_Yk
Brian