Do you already have sub and amp? try to listen to your system without upgrades. Big 3 is strongly "recomanded". Get a voltmeter in your car to watch voltage drops. If you have too much drops, you can try the 2nd batt, and see if it is better. The HO alt is not always needed. But I know it is always better to run the exact same batteries in the trunk and under the hood. just watch your voltmeter to know if you need upgrades. A Btl will be very loud on 1500-2000 watts rms. The AQ 2200 is not a must ! On the cheap, you can find Audiopipe, MB Quart,... Used Sundown,... Thanks for the information man! That pretty much answers my questions. Gunna do the big three today, will get back to you guys after that