what is the cost of an alternator
desert wants $900 is that normal?

Bosch shows that they carry them for the ABZ-engined car. They also show them available from NAPA, Pep Boys, Advance Auto Parts, and AutoZone.<ul><li><a href="http://www.boschusa.com/AutoParts/PartFinder/partfinder.asp">Bosch parts finder</a></li></ul>

These guys have Bosch for $242.35 core return
Rebuilt 97-99 Just enter part # 077 903 015 e
<a href="http://www.europartsdirect.com/">europartsdirect</a>

These guys have two options:
<a href="http://catalog.worldpac.com/eas/catalog_cs/wizard.jsp?partner=eas&year=1999&make=AU&model=A8-Q-001&category=F&part=Alternator">europeanautomotive</a>

On my old V8, i had the alternator rebuilt and upgraded by Avi's Ultranator. He advertises over on Audifans.com and claims that his unit would have upgraded output. Used the rebuilt one for four years without problem. NAYYY, just a satisfied customer.

Seems to me most are the same on the inside. Havent rebuilt one in years but it was a very simple job. Usually the brushs go bad. Just mark the 2 sides of the case b4 you pry it open because some will go together 3 ways.