Bosch rebuild alternators these days are a crap shoot.
As I mentioned above, some people have to try 3 diff alternators before getting a good one.
This tells you something: rebuilders take short cut and do a bad job rebuilding the thing and sells it to you for $200-$250.
Rebuilding an alternator is so easy, I don't know why people don't do it more often.
Two (2) bearings and a VR and you are done.
The only special tool you need is a gear puller ($10-$15) to pull the bearing.