[QUOTE="Valigarmander, post: 1526262, member: 30663"]^^
Roshi blew up the moon at the beginning of Dragon Ball. At the beginning of Z, Yajirobe is over five times as strong as he is. He could blow up the moon if he wanted to.[/QUOTE]
He actually couldn't. This is why Power Levels are deemed "useless." They don't tell the whole picture, they're just raw data. So while Yajirobe is actually pretty strong, even enduring a beating by Vegeta, he has little ki mastery, even Videl has a greater mastery. Power Level isn't all which determines this.[DOUBLEPOST=1427617534,1427617096][/DOUBLEPOST]Also, on Yamcha, if we look at characters from Dragon Ball, moon busting was actually quite a feat, up until Z, when Vegeta set planet busting as the standard at 18,000.
Speaking of planet busting, it's speculated that Yamcha could probably destroy one himself. Here's why:
King Kai tells Goku that Yamcha had crossed Snake Way in a far shorter time than he did, and that he also requested for tougher training than what Goku had received, so he was at least as strong as Goku was at that point, 8,000.
Later, he survives an attack from Dr. Gero, whereas people who are far weaker than their opponents are killed in a single shot (like Gohan VS Cell Junior). This shows he wasn't
too far off from his level.
Plus, during the latter half of Dragon Ball Z, he retires from fighting, but continues training and goes off on his own!
The kicker, if it's considered canon, is that Yamcha offered to fight both Abo & Kado when hearing they're "only" as strong as Frieza was back in his day.
Either way, it's hard to imagine him lower than 18,000 by the end of Dragon Ball GT with all of his training.