I currently have a skar 1500.1 with (2) dc lvl 2 15s and a rockford 490.4 for mids/highs. In the next few months i am looking to double my system. Adding a second 1500 and possibly another amp (so i can run active). I have looked into purchasing about a 240 or 270 amp alt for the front. And at least one battery for the rear. But would i be fine with just getting two rear batteries? I will be running sky high 2/0 power and grounds, 2/0 big 3 under the hood. Would my factory 140 amp alt be okay or would it strain? Not trying to sound cheap but an alt is f**king expensive lol.