regarding subs, i believe your amp is drawing too much from your battery. battery may be in the beggining stages of getting a dead cell or is just on its way out. I would try a new battery with very high cold cranking amps to handle the intermittent surges. I also would add a capacitor (coil) to your sound system. contact local stereo shop and they will get you correct one based on amount of ohm's, impediance, constant actuall amps based on voltage draw. amps say 1000 (500 watts RM), that means (rms) how much continuous power the amo can deliver on avg.. so with the capacitor, t will manage the draw from amp into a continuous flow at i believe smaller surges and converts that into more at the amp input, or help add to the battery draw. lol, its late. as for the car turning off, that might go away after doing this fix. your car can not operate on voltage that low, proly around 6-8 when your stereo is on. and the louder you play it the more it draws. i bet your head lights dim with every thump huh. i will almost guarantee your system will be louder and cleaner after this upgrade as well. it's like using a cordless drill. as the battery goes dead it starts to turn slower and slower. and especially when you start to screw or drill something, anything that puts it under a load, it drrrroooooowwwwwwwnnnnnnsssss dddooooowwwwnnnn. good luck, if the battery and capacitor upgrade doesn't fix the idle and stalling problem, let me know, i shoud have some help for that.
