My needs changed a lot. Sold my SUV and will only be using about 2200 watts all together. Big bass is gone in exchange for sq. I'm not modding my new truck to fit subs or anything that wrecks the structural integrity of it. But I did order 2 20ah LiFePO4 for under the hood.
Caps don't have any reserve for long play. LiFePO I would say is a middle ground between agm batts and caps. More reserve than cap banks, but less than agm. Quicker charge and discharge than agm but slower than caps. My issue was weight and space. LiFePO fits that need. But imo neither can do what a solid bank of agm and a good ho alt can