MP40 will work with WWD but you would have to buy one, $75 and replace the old MP40 driver, white, metal box.
The new whole units, driver, pump MP40W is a wireless unit.
Basically for the used one you would buy a new MP40W driver , I think they are $75 and you would change the old driver MP40, square, metal, white box out for a the new MP40W, square, white, plastic box.
The new MP40W units that run around $425 are the new wirelss units, nothing else to buy, unless of course you wanted a battery backup.
I hope that made sense.
Aquarium Specialty is selling the new, whole, driver, pump, MP40W units with free shipping at the moment.