which kinetic to use?

[brooklyny 2]

hey guys. i need some input on what kinetic battery to use in the trunk. i have a stock alternator and my setup will be pushing around 2500watts. i plan on using a yellowtop up front. so my question is how many watts should my kinetic in the trunk be? the power cell calculator on the site says i should use (2) 1400watt power cells. which will be costly to me. any cheaper solutions? do i really need that much? input please and thank you.