A-3 Alternator / V. Regulator

Has anyone replaced the voltage regulator (VR) (028-903-803-D) on their alternator ?
Anything I need to know ...tips or insights ?

Also ...any info on symptoms indiacting failure?

A question...what amps is on the A-3 TDI alternator:
70A= 028-903-025-H
90A= 028-903-025-Q
120A= 028-903-025-S

TIA
Herm

Every A3 TDI that I've seen has the 120-amp alternator.

Voltage regulator is built into the alternator. I have not touched this, although with 376,000 km on what I'm sure is the original alternator, it's a concern area ...

Bad voltage regulator could cause the "battery" icon to stay on or flash intermittently while the engine is running, or it could cause the output voltage to be outside the allowable range. I don't know how you would distinguish between voltage-regulator failure and any failure of some other part of the alternator - end result is the same since the regulator is inside: the alternator needs to come out and come apart to get fixed!

pretty sure all are 120, the gassers 2.0 use the 90 alternator.

My battery was consistently boiling over (eventually eating through power steering fluid reservoir) and I replaced the regulator and put in an Optima battery ($120). I pulled the alternator out which was a real pain, then had a shop replace the regulator and test($75). No problems since (maybe 20K ago). If I had to do it again, I would try and change the regulator in place. I think it could be done.