I just put in a Sealand low profile this week. Easy to install, bought the universal adaptor.
Just a note. Me being the typical, mechanically inclined male, I decided that it was so simple that I didn't need directions.
I started to try removing the existing flange before I stopped and read the directions. DON'T remove it. The adaptor goes right over the top of it and screws down. I was able to recover from my mistake.....
The toilet works nice, with a ball valve instead of the old blade type. Very smooth with a positive seal. I like it.