Raditz's secret is that he is always SSJ3, he had evolved so far beyond anything else his normal life was just walking around SSJ3, hence the regular hair.
But his downfall was mistakenly dying while doing that Dragon Ball thing of starting out low level just mucking around then going "Haha, you were holding back? I figured as much, well so was I!" *powers up*
Usually we repeat this 3-5 times a fight until finally 14 episodes into it they're actually fighting 'for real' now.
Poor Raditz got caught out early, woops!
Also I dream of one day Nappa's moustache turning SSJ.