Parts in the tank are the same.
The seat is the same.
Trapway design is the same.
The Utramax flushes with more force, the higher tank is the reason.
Either toilet will work fine. I've installed plenty of both.
Terry...Own a home built in 1985 with the original toilet still intact. We are in the process of remodeling the powder room downstairs which is roughly 5 by 5 and cannot decide between the supreme or the ultramax. The new flooring will be bamboo so our concern is of course clogging and leak issues. Is the ultramax more expensive in terms of repairs in the future? Dont know either the power of the Supreme...in terms of grams of waste per flush??? Is the ultramax worth the extra money in terms of function and reliability. Just want a toilet we can rely on for the long haul.... help. Joe