Running any pump at the maximum rate will present some form of motor noise. The loudest part of my tank is the fans from the light fixture, so I have had no noise issues with the 6040s at all. Im likely due for monthly pump cleaning in the next week or so, I can easily pull out the entire pump and controller when I do that and you can give it a whirl for a few days if you are on the fence. On the lowest setting (assuming you arent using an Apex to control the pump) it puts out about 50 gph... which is pretty low flow. If you run it off the Apex, the minimum speed is 30% (which is around 400 gph) which still seems like plenty slow enough in that size of a tank. Clearly mileage will vary, but placement of the pumps and flow direction is going to be more important than sheer velocity. I think in your case, since you have the return at the top of the tank for water movement, I would place two small powerheads at the back wall of the tank, one on the right, one on the left, about 2/3 of the way down and program them to run the same pattern/function, but with a 15-20 minute offset in the pumps. That way you get some random chaoticness, but there is also some overlap as well. Thats how I run my WAVs and Gyres. My 6040s are simply on 85% without variation. With a small tank like yours, its gonna get cluttered really fast with all that equipment in there...
At least you can cook your eggs there in the morning 
