[Shotimes] 95 ATX Alternator problems

[Mike]

I'm at a loss to figure what to do with this alt. , with only 60K miles.I've
had it repaired 3 times, and the guy tells me he has changed the VR each time.
But when the car starts, the light comes on, and won't go off until it hits
1800rpm, and after a month or so it comes on permanently.  He gave me a 2 year
warranty on the repair, but I think he's not going to touch it any more.
Looking at Rockauto, there are 2 VRs listed, one at $143 and the other at $87.
Are they both the same, and it seems a little high when I can get a rebuilt
for around $150.  What is the real story on these things?  Also the diodes
aren't shown on Rockauto; are they available, or do they ever go out?  Looking
for a little help here.
Mike