ryu vs [COLOR=deeppink]dan[/COLOR]
ryu sf4 vs dan svc version
fight is about coolness,preferences(which you like better),and strength
if you prefer to choose other version's then okay.
i for example like dan more for being ryo-like on sf
but now changed for gouken
he could haowever beat ryu if he would beg from akuma
to teach how to throw man's fireball
IIRC, Dan was expelled from Gouken's dojo, 'cause Dan was training only fueled by revenge (Sagat killed Go Hibiki, Dan's father).
So I think that, if Gouken continued to train Dan, he would have tapped the Satsui no Hado.
However, since Dan is one of the weakest SF chars, he wouldn't be able to control the Satsui no Hado at all (unlike Gouki, who masters the Satsui no Hado, but is capable to contain is strenght and not go on a random killing spree).
So, an "Evil Dan" would either be a mindless berserk, or simply destroyed by his own energy. So I think that even if Dan would have been trained by Gouki, he wouldn't ever be able to defeat Ryu.
About normal Dan vs Ryu... Joke char vs the hero... Quite easy to determine the outcome 😛