How much power do I need?

[magillaru]

Other than the big 3, which you're already planning on doing, start with an AGM up front and one in the back and check voltage after that. I recently added a battery in the back (group 31) and it made a world of difference (very little voltage drop)....the HO alt is definitely an option but I would take the battery route first.

Good luck!

[csshakka]

As a reference, I'm running a sundown saz1200d and a Rockford fosgate r300-4 off of stock 136amp alternator, stock SLA battery up front, and an AGM battery in back (same size as front battery). Prior to adding the second battery, my lights dimmed pretty bad. Afterwards, no dimming and never noticed any voltage drop that I should be worried about.

Edit: also did big 3

[Cj Kumz]

As a reference, I'm running a sundown saz1200d and a Rockford fosgate r300-4 off of stock 136amp alternator, stock SLA battery up front, and an AGM battery in back (same size as front battery). Prior to adding the second battery, my lights dimmed pretty bad. Afterwards, no dimming and never noticed any voltage drop that I should be worried about.

Edit: also did big 3

Nice man. How many amp hours are you batteries?

[csshakka]

As a reference, I'm running a sundown saz1200d and a Rockford fosgate r300-4 off of stock 136amp alternator, stock SLA battery up front, and an AGM battery in back (same size as front battery). Prior to adding the second battery, my lights dimmed pretty bad. Afterwards, no dimming and never noticed any voltage drop that I should be worried about.

Edit: also did big 3

Nice man. How many amp hours are you batteries?

Not sure on stock battery, but it is a group 34, so I would guess about 55ah. The one in the back is group 34m Duracell marine deep cycle agm - 55ah from SAMs club.