Alternators, who runs what?

I have had about 4 alternators go bad on my valiant.
They either fall apart on the inside or start sparking with rpm and the + post.

All from autozone.
I even upgraded after the 2nd one, but still have returned 2 more since.

Getting sick of turnin up the wick and having my volts go from 14 to 10 on the gauge, definite short in the unit thats for sure since the car has been rewired completely.

I've been thinking about a denso unit and some fabbed brakets.
Anyone run 1 of those?