[chassis]

Finder has some $40k 981s listed that look OK.

In my several years as a Porsche owner, the most egregious flaw in my mind is IMS bearing failure on flat-6s of certain years. As always with any car, the newest and lowest mileage for the price point, which ticks all of your boxes is best.

Resources:

Finder.porsche.com
Rennlist - friendlier and more helpful than most car enthusiast sites
Bringatrailer
Cargurus
Bimmerpost - lots of people here own P-cars
Wikipedia for specs

List of things to do from a thread on the first page of the 986 section:

“Be prepared to replace if it hasn't been done:
1. IMS bearing
2. clutch kit/flywheel
3. RMS
4. AOS
5. Variocam wear pads
easy DiY items...
6. Chain tensioners
7. Serpentine belt
8. Engine/Cabin Filters
9. belt tensioners
10. flush fluids and refill
11. battery
12. Oil change”