Hi guys. I have been struggling with this decision for two months now. I need some opinions. I have the power to either use two re audio xxx 12s or four re audio sxx 15s. i am wondering which everyone thinks i should go with. i am looking for the lowest and loudest. I have plenty of room for either way i go. The reason its between these subs is bc i already have 2 sxx 15s and 1 xxx 12 and i have the money to buy some more stuff. the only one i have installed is the xxx. so i dont even have a clue what the 15s would sound like.