ORIGINAL: Bax
According to the Great Planes R&D people, the instructions don't talk about making the plane a true amphib because there isn't a way to seal-off the retract wells against water incursion if you install retracts and want to fly off water. Basically, you configure it for water or land, not both.
Well thats a false advertising lawsuit waiting to happen.
From the greatplanes web site:
And by substituting optional retracts for the included fixed landing gear, you'll have total access to land AND water with the same plane!