I have a system in my Cadillac CTS not more than 1000 watts and want to put another battery in the car soon. I still have the same delco battery that came from factory and was told that only battery that can fit is Delco battery. But I want different battery. What type of battery would fit in my 2006 Cadillac CTS other than Delco battery that comes in it? I would really appreciate your useful information. Thanks.