The Marvel Universe

Since the gizmo would allow them to affect their destination to a great extent, that meant that in a universe where super-powers existed, the four travellers could hold such powers.

Now, there were primarily two universes of that kind, which were for some inexplicable reason now as the "Marvel" and "DC" universes, respectively.

After some checking, the four decided that they would become superheroes in the Marvel Universe, which seemed more exciting than the DC one, not to mention that it was inhabitated by a much larger selection of busty superheroines in tight little outfits.

Naturally, apart from whatever new powers they would give themselves, their real, sexual ones, would remain in place, guaranteeing them a whole lot of fun.