When did Goku first SSJ4?
Janu
"The Mightiest!! Goku Becomes Super Saiyan 4!!") is the nineteenth episode of the Baby Saga and the thirty-fifth overall episode of Dragon Ball GT. This episode first aired in Japan on
Janu.
Why does SSJ4 gogeta have red hair?
While this theory is a little hard to believe, the other recurring theory which even I personally believe makes more sense is that SSJ4 Gogeta's looks a lot like SSJ4 Goku(apart from the color change) and the red
color hair was done on purpose to further distinguish the 2 characters.