Welcome future Boxster owner! You should check out Mike Focke's webpage on Boxsters:
MikeFockeBoxster
He gives info for new buyers, sellers, and info on maintenance and DIYs.
You definitely want a PPI done by a competent Porsche mechanic. Also the fact that a lady babied the car is nice, but IMS failure can occur regardless. You'll want to check if there's any oil between the engine and trans area, RMS and IMS are above this area and these are two of the more important things you'll want to check.
Despite some problems, Boxsters are great fun to drive and own.