Its easy. But I had to buy a new adjustable wrench, 12" I think, to fit the large nut on the bottom. I also had to wrap some tape around the bearing cylinder. There was a fair amount of play with it and the hole in the plinth.
I just replaced the platter on my Scoutmaster with the superplatter and it was quite easy and worthwhile. A expensive tweak put one you can hear the results from which in this hobby doesn't always happen. Luckly I had a big enough vise grips to get the nut off.