Kit Two is designed for amps up to 175 watts x 2 (350 watts total RMS). It includes the same array of cables as in Kit One but increases the thickness of power and ground cables to 8 gauge and includes a 40-amp SE fuse to handle higher current flow. If you're planning to push a subwoofer or two at extra high volume, Kit Two is a good choice, even if your amp puts out less than the guidelines call for. Kit Three is designed for amps over 350 watts total RMS. Power and ground cable thickness increases to 4 gauge, a 60-amp SE fuse, and the patch cord is upgraded to the Musica 200 Series, which uses heavier insulation.