I've been using an old G-K RB400 for a while now with my Carvin 2x10. It sounds great for coffee shops and small bars. Problem is, I just joined a hard rock band with two half-stacks and double bass drum out the yin-yang. My rig can't keep up-it's two hundred degrees by the end of a show. Impedence set aside-do I need more wattage in a new head with more speakers? Or could my 200 watt head drive something bigger (louder) like a 4x10 or a 2x15? Would that be loud enough?