Thanks for you insights Scott.

Luckily for me, I own a AutoBody shop so repainting is less of an issue. The car does not have much in regards to maintenance records. My main concern is the 68k miles ... Should a good PPI cover most things such as engine status, body/frame inspection, etc?

 

If it is me, I would pass it. If you want to keep it for sometime. There are some 30k-40k miles at good price. May be look in 01,02 year. It would not matter much from 03 if owner take care his car. Another $10k is worth spending. If you use it another 30-40K miles in 3-5year. It will save you some in repair. ( say value of repair $3-5K come faster in 68K miles car.) Porsche repair and maintainance is a bit pricy. When you sell it, you will sell 60-70K miles car compare to 100K+ miles. Sell price should be different.
(It might be diff story, if you know owner of this car and how he drives/maintains it.)

 

A good PPI should cover those things, but not all PPI's are done the same. So make sure you use someone that's very familiar with 996TT's and their nuances. Also, get a leakdown test included. Make sure they also test for Type 1 and Type 2 over revs as well as 2nd gear pop-out. 2nd Gear pop out is pretty easy to test for if you know what you're looking for, otherwise it wont show up. Basically you drive down hill while in 2nd gear then let off the gas and let the car's engine slow it down, if it pops out of gear, you've got the dreaded 2nd gear pop out. I'm pretty sure that's how to test for it. There's numerous threads about it, so it's worth searching and acquainting yourself with.