For reference, here's an '87 Carrera 3.2 Targa that I passed on a couple of years ago.
It seemed perfect. It looked fantastic and appeared to run great. Original owner, original paint, perfect black interior, newly recovered Targa top. 103k miles.
The owner was asking $15k. I was almost ready to make an offer of $12k (but probably willing to pay $14k). I towed it 40 miles to a very well respected Porsche shop for a PPI.
I spent the next several hours at home, nervously separating hundred dollar bills into neat little stacks of ten while waiting for the phone to ring.
When I got the call from the shop, I was floored. While the car appeared perfect to me, I was told that I should only buy it if I could get it for five grand. There were so many expensive little (and big) things wrong with it, they said that it would cost another fifteen to make it right. And I thought all it needed was tires, a battery and an A/C recharge. I knew that it would need a clutch before long.
I was very disappointed, but happily forked over $450 to the shop for the PPI, which was the bargain of a lifetime. I didn't even make an offer on the car and trailered it back to the very disappointed owner's home. The owner got a copy of the PPI and spent a long time speaking with the shop owner.
Several months later, it was back on Craigslist, asking $15k, same phone number.
Besides, Targas are for Bob Costas.