I have a 1995 Carrera 2 with 17 inch wheels. It is currently wearing Pirelli P Zero tires with about 8k miles. The rear tires are almost fully worn on the outside two inches of the tread while the center and inside are still measuring at 5/32. This is consistent for both rear tires.

Is this a result of incorrect pressure, incorrect camber, what??

 

John,
It sure sounds like you have positive camber. Generally, if the tire pressure was too low, you'd be wearing both the inside and the outside edges. Conversely, if pressure was too high, you'd wear the middle of the tire tread.

A good alignment shop should be able to bring the top of the tires towards each other (more negative) to help.