Meh, Master Roshi could destroy the moon (our moon is huge - 2% of the earth's volume), meaning that saiyan saga base goku (no kaioken) could blow up the earth (as could Vegeta).
The sun is 1,305,700 earth volumes, and 330,000 earth masses - in other words, when Frieza fought Goku (in the Frieza Saga), he would still have had to increase his power level by a factor of ~22 (going by mass) or ~87 (going by volume) to destroy the Sun.
He would then have to increase his power by a factor of ~10 trillion (going by volume) to destroy the solar system.
In other words, Frieza, circa Frieza Saga, times 870 trillion, equals solar system buster. Forget star clusters, galaxies, or universes.
There's plenty of room for power increases