Tony,
noise was the main thing here. I don't have an enclosed stand to hide the pumps in and reduce the noise. So outside they went.
The MAK and the 2MD both were and are awesome. But silence is golden.
There is a fair bit of flow in the sump but the baffles are far enough apart that there really isn't much in the way of turbulence. The flow is up yes. But noise or bubbles isn't. Which is nice. I made the sump with an increase in return pump size in mind. I just didn't expect it to be so soon.
With both T4's going the tank temp has gone up just shy of two degrees. Right now I am sitting at 80. Which is nice. I'll probably add a fan over the sump that comes on when the tank temp gets past 80 this summer. Just need the thermistor and build the controller.