Drive the car and listen for the whine from the rear. Remember, only a small percentage of 968s (<5%) had the pinion bearing issue. I've had 4 and none have had it. The few that did have it have mostly been repaired at this point. Time and mileage factor into the belts. It looks like you are okay mileage-wise. Most feel the job should be done every 5 years no matter what the mileage. Asd far as value, the car sounds great and the price sounds fair for a cared-for example.