After I built my Tubas this past Fall, I got a Behringer DCX and two Behringer EPQ 1200's and they've all done great for me so far. I sold my Mackie SRM 450's and 60 lb M2600 amp, my 18" subs, and some other stuff. I've been very happy with the decision so far. One of the 1200's is for tops and it barely lights up even when it's pretty loud. The other I use one channel at the moment to drive the pair of Tubas and it provides all the voltage swing I need for those two, also plenty loud. It can get over 50 volts each channel and I've got room for two more subs on the other channel later. I have it limited to around 48, but have not pushed it over 40 volts if I remember correctly.
Those amps do nothing but amplify and all the processing happens in the DCX, which I really like, after getting it figured out. I'm adding a DEQ this week for EQ, RTQ and AutoEQ, and hopefully it's from a good batch. The EPQ has crossover on it, so in the event of a failure of the DCX I could still get make it though a gig running subs on one side and tops on the other...actually as long as I have at least one amp I should be able to squeak through, so there is some fault tolerance in that area of my rig....did I just mention "fault tolerance" and "Behringer" in the same paragraph?///
Still, something to consider as you plan your rig. Good luck on your plans.
Donny