If you can get any
Iwaki for $40, you win.
Yes, my pump is a WMD (US made motor) and the MD versions are Japanese motors. There's probably a +\- $50 cost difference between the two depending upon model.
Here's the US version of the same pump (30 RXLT) you listed from Marine Depot:
EDIT: Interesting...when I click this link it takes me to their home page, but if I paste into the browser it takes me to the pump.
I've only used Schedule 40 PVC fittings with my Iwaki, so I can't speak to limitations of the nylon threads on the pump. If you use QD fittings, it should be a moot point. Since you are purchasing used, just be sure everything looks good. If you are in doubt, remember that March pumps are $125 and have been proven to work well...that's why I am using a March and not Iwaki or Little Giant.
Hope this helps!