Help: Alternator needs replacing at 42,000 mi? Price jacked up in past year?

[socratic]

Because of some worn pulleys on the alternator/waterpump area needing replacement, I took it into the dealer.

The bad news is that they believe that the alternator is contributing to the noise and feel it needs to be replace. The initial estimate was maybe $400 for the alternator.

Now I'm told that the dealer has discovered that Porsche has jacked up the price by over 100%. Retail cost (before installation!) of the alternator is now over $1000.

First, is it possible that there is a worn out bearing inside the alternator itself or a worn or bent shaft that is causing the noise and could it have happened at only 42K?

Second, is there an alternative to a full retail price OEM Porsche alternator? If so, where and what? Can third-party alternators be trusted? An alternate source perhaps?