I have my MT in a 3 cube box tuned at around 31hz. Its loud and I like. I would go bigger but that would require me to chop up the car to get the box in.
Depends on what you want to do OP. I have stock alt(95A) stock batter no Big three teo stinger spv70's in the back powering an IA 40.1 3600wrms and i dont see voltage drop past 13.2V. Just check it out set your gains right and see what you need.