Digimon Xros Wars Episode 6

[SnK]

2 Digimon = Champion level or higher.

3 Digimon = Ultimate level or higher.

4 Digimon = Mega level, higher or lower.

I also share the same idea with that as Shoutmon's way to evolve and gain strength levels equivalent to that of higher forms.

Though X3, seems to look like a Mega level already just minus the Star Blade. X4 can be somewhat equivalent to Mode Change.

But I still lean on the concept that Xros Wars doesn't give too much jack on Evolution logic. But, they could still adhere to that as the episodes go on.. I mean, it's like advancing through later stages in a game. Enemy Bosses get harder later on.