If your car has a manual transmission your alternator has a replaceable clutch pulley. This is the case for model year 2000 forward for the 986 cars. I'm not sure about 987 models.
My alternator clutch pulley failed and the alternator itself was just fine. Here is a link chronicling the replacement of my pulley:
Clicking Noise Solved (Alternator Pulley)
Best of luck,
ddb