In February we bought a 2005 SunnyBrook that had the Aqua Magic Style II toilet. It needed about $90 in parts so we replaced it with a Dometic 320 because we liked our 310 in our last 2 TTs but wanted the elongated bowl. Our floor flange allowed the bolts to be put in the correct position but you won’t know that until you remove the existing toilet. We haven’t had any leaks
It is my understanding that if you don’t drain the line on the 310/20 the water valve will freeze easily and start leaking.