Budget System ?

I had a customer bring me in a 94 Buick Park Ave with Complete Stock radio system in it.

He dont have a whole lot to spend left after getting budget stuff off of me

4 Audio Pipe TXX-N1200 1200 watt dvc subs in Slot Port Prefab Boxes(Its what he wants for now)

2 Crunch Power Zone 1500.1 Amps for subs

1 Crunch Power Zone 1000.4 Amp for Highs

Fusion Power Plant 6.5 Comp Set

Fusion Power Plant 6x9 2 ways for rear.

JVC KD-G820 Head unit.

3 sets of Rockford Fosgate 20 Foot RCAS

I am wandering what the better way would be to go for a budget....

Big 3 and a extra battery or Run Big 3 and a Cap if so how big of cap....

Also whats the best way to run big 3 in this car? I am thinkin under it with some protective sleaving of some sort but I was wandering if you have any ideas.

Also this is just a Daily System for a college kid.