You using these for your build with the basement fish room and 90G DT? If so, the Barracuda will be more than enough. You will need some massive overflows to even approach the flow put out by it. I have a basement sump with a 150DT with (2) 1.5in Overflows and I can't handle the full output of the Barracuda. And that's after teeing off for the frag tank, and 3 reactors. In addition, unless you have a bunch of outputs, you are going to be putting out some serious laminar flow that nothing will like to be in front of. I can't have anything in front of my (4) outputs. AND, all that flow will have to go through your sump, with all the bubbles (fish room mist) and turbulence that much water creates. With the type of powerheads that are out there these days, I would minimize flow through the sump and the associated return pump, and maximize the flow in the DT itself. You'll have plenty of water going through your sump regardless and it's much more efficient to move the water in the tank.
Get rid of the Dart, or keep it as a back-up, I've had one for a few years but the Barracuda just won't quit. But it's not the type of pump you can run to Petco and pickup, so I am always worried what I'd do if it did. Having the Dart makes me feel better.