It could be any amount, so long as they're strong enough to be deemed capable of handling the same Goku that tore up Rild on M2. That amount can be lessened somewhat when you consider they don't tire out and are apparently invincible in Hell, while Goku will eventually lose stamina.
I agree with Pyrus on the Rild idea. He's the last person to fight Goku that they have any contact with. So Freeza and Cell should have an idea of how strong Goku is on M2, and look to surpass that.
Even if I had Freeza and Cell 3x SS Goku's power, which makes them monstrously stronger than base Rild, they'd still end up quite a load weaker than SS Vegetto.
I think a more interesting discussion would be what kind of gap exists between Cell and Freeza. I'd say that Cell is still stronger based on his condescending tone towards Freeza, but by how much?
I think a more interesting discussion would be what kind of gap exists between Cell and Freeza. I'd say that Cell is still stronger based on his condescending tone towards Freeza, but by how much?
Enough to put Freeza down if the need arose? That's about as far I'd be able to tell. Maybe the Perfect Files will be fully translated one day and there will be some new info to use.
Its worth noting that Freeza actually lasts 2-3 seconds longer than Cell does in their initial fight. All things considered, they seem to operate as equals, though I always give Cell the obligatory bump up.