Please Help: What size amp should I use?

Kenwood KAC-8404 Amplifier features a rugged cast aluminum housing more than 40% smaller than its predecessor, but it would be to pump still 50 watts RMS into 4 channels – ideal for enhancing the performance of the front and rear speakers in your system. Or you can use the amplifier 2-channel mode, the bridge and a few U-boats with 180 watts RMS without any effort on your car’s electrical system.