looking for some 12s under 600$ going to be powered bu t2500bdcp and have about 12 cubes to work with. I was looking at the dd 600 redline series and the sq hds3
Don't let that 600 RMS rating fool you. They can easily take 1k, and if you know what you're doing, they can handle 1,200-ish.
However, with that said, you won't go wrong with any of your choices. But remember, 3 of the SoundQubes (1200 RMS models) would be a waste on 2500 watts. They wouldn't shine the way they should.