Hi Aaron:
Unless you're a concours fanatic looking to preserve 100% originality, there's no reason not to install a modern alternator. Take a look at this srticle about the conversion from a generator to alternator:
http://www.geocities.com/motorcity/d...37/duealt.html
I've always used the latest Bosch internal regulator type, but as you can see in previous postings, others have used the GM units. I like the fact that the Bosch units look more original, are made for the higher rpm range of an Alfa engine, and also that an adjustable internal regulator is an inexpensive upgrade. But, I haven't heard of any problems with the GM's, so that option is certainly viable.
Regards,
Dean
Lutz, FL
'74 & '87 Spider Veloce's