in order of pumps its always been the 350 < 355 /w no top = 350 /w top < D5 < 355/w top.
Meh.. theres more pumps.. but i cut the ones u would never see, like the RD-30, and the 24V D5 Strong.
Having 2 350's will give you about 33% more flow... which is higher then a d5.
And head pressure is 100% carried over on pumps in a series.
The hard part is getting a top to use dual DDC's or getting the bay res, because they're pricey.
but if ur heading into dual DDC territory... a dual top + cyclender res might be a solution over the bay res.
Here is an example of a dual top:
You would do a simular setup like this...
Cyclender res.. tied down to a pump short.. and then out.
you wont be able to use that exact one.. but there are options from watercool, eK, and koolance.
And here is a D5 next to an RD-30..
And a D5 + Rd-30 next to a PA120.3
The D5 is a big pump... dont think its tiny.
If your set on the D5 tho... there's always this:
That turns into this with just cylinders..
lol ViVi u see now why i am trying to nudge koolance at ya.
They make watercooling almost noob proof.
Koolance listens to advice we throw at them to make things easier.
They have only been good to us since they did the 180 degree face change.
And it was my most hated company, face changed to my favorate company, all in a short span of 2 yrs.
Koolance is even trying to make things more noob friendly, by making rad puncturing a thing of the past with this guy:
There still work in progress, but im working with koolance to make them more friendly on other rads.