sell the hcca buy a zcon or evil. run it on the bc2000 and sit n smile and think damn this is so much better than my hcca was.. But why? If he is happy with his current subs, no need to spend more cash. Yes, the Zcon and Evil are both amazing subs, but they have their own audience and their own performance perks. If the HCCA's fit his goals, no need to change. And OP, I've personally have always liked sticking to one, makes things simpler. But I also don't advise to run at .5 daily. You can, but definitely not necessary.