Well, no more replies from them. I say stay away from this, and buy a March pump instead.
That said, I did solve my problem. I just attached some silicone hose to the problematic thread and used a worm clamp. Then I put the QC on the other end of the hose. I'm going to be building a box with a switch to house the pump anyway, so this works fine for me.
The pump itself works fine, and it's really quiet. I tested it out by running water through my system, and it worked quite well. I'm brewing tonight after work, so that'll be the real test, I guess.