do all D5 style pumps interchange?

like the title asks can i just put this manufacturers d5 pump in that manufacturers reservoir, and vice versa?

So long as it's for the D5's. why not. It should work fine.

I don't know, it just looks like everybody has a D5 style pump.
I'm looking at a monsoon reservoir that takes a D5, I have a vario that cools a 9590 and A titan that has to run wide open.
I have a D5, non vario laying around doing nothing.
the monsoon reservoir is going into a cpu only rig that will not need to run wide open so, I was thinking it might be mix and match time.

Ya the standard D5 and the D5 vario, along with the swiftech and other brands custom variants. They all mount up the same and have basically identical impellers. Its just extra options on the electrics that the custom ones include.

Yes, it should work. Along as it states for D5s you're good to go.