Don't think he's class 100 (unless you amp him for the purpose of this thread), at the absolute best he was equal to young Colossus who was described as Class 70.
Sure, you could argue that even as a teenager, Colossus was class 100 with feats like fighting Gladiator, briefly ko'ing the Hulk and lifting the spaceship in Secret Wars... but Warpath simply lacks the feats, his best one is probably getting props from the Juggernaut or preventing Demon Bear's jaws from smashing him.
I'd like WP to win, but simple truth is that he can't; IF has been way more impressive.