The capacitor I'm using is 2F and will be wired near to the amps in the boot, it's used to stiffen the 12V supply for ICE installs that require a large amount of current.
I will be running two AudioBahn Subs (AWT12X - 1ohm, 2KW RMS power handling), each sub will be driven by an AudioBahn A18001DQ amp (1800W x 1 @ 1ohm).
I will probably need a second battery but have not got round to this yet, anyone fitted a second battery, if so how did you do it and has it caused any problems so far?