The driveshaft bearings on higher mileage vehicles may become noisy.Google+
Car Problem Reports
Porsche 944 Driveshaft Bearings May Become Noisy
Porsche 944 Problem
Drive Train Affected: Manual Transmission
Visitor, 1990 Porsche 944, Manual Transmission, 130,000 mi
Torque Tube/Driveshaft bearings start to become noisy as they approach failure. Solution is to replace torque tube bearings. pretty difficult job.