Sony knows that many vehicles just don't have space for a big amplifier, so they've created the XMS400D 4-channel amp. This tiny powerhouse will blow your mind — blasting your front and rear speakers with 45 watts RMS each from a chassis that's the size of a big candy bar.

You'll get up to 600 watts RMS of bass power with Sony's XM-GS100 mono amplifier driving your sub. For maximum reliability, this compact amp sports a hefty heatsink that shunts off the heat that's generated when the amp's working hard. The XM-GS100 will also protect your subwoofer, with a Dynamic Distortion Suppressor circuit that rounds off the corners of dangerous square waves, minimizing the destructive effects of an overdriven signal.

Sony's XM-GS4 4-channel amplifier will drive your whole system, sending 70 watts RMS to each of your front and rear speakers. Or you can switch the amp into 2-channel mode to power a couple of subs with 160 watts RMS each. This compact amp sports a hefty heatsink that gets rid of the heat that's generated when you're pushing your system hard.