Kenshyuk

And the fact that -none- of SSj 4 Gokuu's ki-ko-ha's, even those at full power, even destroyed as little to a planet and/or a star, let alone a few million galaxies as Shin Buu should have been fully capable of(and breaching the fabric of the space-time continuum, while he's at it, with the force of his breath, lawl.)? Given this, if you apply canon logic into the equation, he'd no stronger(if not much weaker) than Muten Roshi at full power. However, with GT logic(as if such thing even exists)....that's a whole 'nother story.