The epic Freiza vs Goku debate

[Super Buu]

Originally posted by Mighty Dabura
And in the fight against Freiza he was using Kaioken at such a high level of skill that nobody but Kaiosama knew about it, so at that point it's essentially the same as his base power level.

You could still see the red aura. Tien and the rest just weren't as versed with Kaioken, and were too dumb to see it.

It's an interesting theory, but I think Vegeta just never caught up to Goku once the latter got SSJ. In DBZ, the stronger you are the faster your power level rises (it's always exponential) and since Goku had SSJ for so many years before Vegeta finally achieved it, he just put a gap between them that never got closed. Training at 100x gravity was just trying to emulate what it would be like to use SSJ, what with the extreme drain. All the while, Goku was still gaining faster - that's my theory, at least.