FTO AUSTRALIA

Hows everyone going? I'm going to put my car in Melbourne Autosalon & planning to show off my under car LEDs, interior neons, 2 amps & 2 12" inch sub with the indash monitor & PS2. After doing some research, ctek battery chargers are pretty good, you can put it in supply mode & basically use the power straight from the power without using to much battery power, the problem is i have no idea which one to choose, i did notice more the amps, more the cost, a guy from battery world said "15-25 amps should be ok, but even 7 should be ok".....so does anyone know how manys amps is descent for my FTO? Thanks heaps
BJ (DRFTO)