What alternator for 2007 Yaris?

[Cartel]

My alternator has been giving me trouble and has a low charge voltage.
I took it apart and cleaned the regulator, checked the brushes and cleaned up the commutator and it all looks good (60,000KM).

The problem is it only charges at 13.6v-13.8v with nothing on while another identical car charges at 14.2v-14.4v.
I checked for voltage drop at full load (130mv) positive and negative (0.001mv) and AC (0mv)
I think my audio amp may have hurt it somehow. (guessing)

I am looking for a heavy duty alternator if possible or I guess I'm going to replace the regulator and see if that helps.
Could the ECM be damaged somehow?

I can find my alternator (27060-21150):



But I also see one with a bigger heat-sink on the regulator and a bigger body too:



Is there a better version?
These both say 80 amps but 1 looks much beefier.

My audio amplifier only uses 40 amps.

Thanks