Alt advice

I was also thinking of upgrading alt for bigger one.
But after I made electrical upgrades, rewiring alt and bulkead connetor, removed alt meter and rewired lights and new swiches and relays.

After all those and now my idle voltage is 14volts. And I have bigger lamps and speakers.

I would make sure all electrical system are good condition before putting bigger alt, its like putting more pressure to leaking pipe, worst case it will brake your new alt faster