I don't think series will work with this one.

The first pump will have an inlet and outlet that are equalized in the same area, so there will be little to no resistance and that first pump will simply act in recirculation to itself (recirculating in a mini loop). The second pump will have two isolated areas of pressure, so I think running this in series outlet of Pump #1 to inlet of pump #2 won't work as you're thinking to get "Series" pump benefits. The only way to use two pumps with this is either in parallel with Y splitters (which isn't any good with watercooling with our high restrictions), or use it to feed two separated loops that share the reservoir.

I could be wrong, but that's how I think it will work.

We need to convince Paul to make the top reservoir two separated ones with two fillports. That sort of design should allow series on one loop to work right. It would also allow you to either use two different fluid colors, and/or allow you to run two loops with different water temps.

Otherwise I really like the idea, especially if those vibration dampeners work right.