What do we like for batteries nowadays?
 

I hear there are smart batteries with chips & shit in them now.
Is this better than my $30 golf cart battery that lasted 3 years?
I'm not racing for the championship, and my miata only gets driven about once a month.
Priorities, in order: cheap > locally available > discharges slowly > weight

Agm batteries from farm supply stores are usually the best bargain for power to price ive found, auto parts stores are wallet molesters.
i know nothing about sizing so i just go for the same group size as stock and strap it in but our motives align, you do you.