Today I installed a 4 x 150W RMS amp and a 10" subwoofer in a homemade ported box in my GFs JK.
The stock front speakers are connected to channel 1+2 and the sub is connected to channel 3+4 (bridged).
The stock speakers in the roll bar are still connected to the radio.
It sounds so much better than before. And its very loud. Topless with 80 mph I can only hear the music and nothing else like the diesel engine or the tires.