Product review (5 stars): Relatively easy swap.
It fit relatively easily into my Sub Zero #542.  Everything needed was supplied plus a few extra things not needed.  Fan motor extended about .5 inch further forward but there was plenty of room and it still fit the shroud well enough.  I used the old fan and one new rubber vibration insulator but did drill a hole through the rubber to fit the locator pin in the fan hub.  Very easy and everything matched well.  There is so much space in my refrig to work that it's an easy swap almost plug and play.  Youtube will tell you how to do it.