Hmm, very interesting..
They are actually incredibly loud on the rad.

For now i think they are fine, but I may change them for some better ones if when I add a GPU waterblock with a new card near the end of the summer.
Thanks for the heads up!

Also, I can see how the o-ring can be easily forgotten. When I pulled the top of the pump off, the o-ring stuck right to it and I didn't realize where it was.