whats the difference between a max stat and a super max stat

Max stats are pets with the base stat of 100. Super stats are pets with even better stats, basically.

The previous post is the tl;dr. Here's a longer answer if you want more details.

Max stat pets have the maximum possible BASE stats you can get from breeding. This is 2000 health, 200 mana, and 100 each for strength, intelligence, dexterity, and agility. Example max stat pet. (Note that max mana is relatively new, so you may see older pets with every stat except mana maxed, like this. These were considered max stats at the time.)

Super stats have the max BASE stats, PLUS something called WILD stats. Wild stats come from pets caught in the Lost Grove and can be passed onto offspring, though they go down every generation. Anything after the + sign in a pet's stats is the wild stats. Hypothetically a super stat could have anything from (100 + 1) to like (100 + 60), but generally stat breeders try to keep it as high as possible. Example super stat pet.