How can you get all dragonballs on Dragon Ball Z budokai 3

Dragonballs are either achieved by destroying buildings / obstacles in Dragon Story Mode or randomly by winning tournaments.
I would advice you to play special saga on easy , the fight "Goku the super sayian" vs the evil namek lord slug. Alot of buildings to destroy and not a long fight if you DON'T activate the R3-Event when it appears. Fastest way to do it.