Lol, brazilian jiu jitsu will work horribly in a street fight situation sorry.
also, kyokushin karate is effective in the street as much as muay thai is.
I do both, as well as taking MMA classes, so i know muay thai as well.
ps Go Kan Ryu is money karate, and is basically a pyramid scheme...
I listen to it the first time without taking notes, the second time i take notes and think over what i heard, not really a spectacular method but i might as well share.
it depends on what style of karate you do as well, kick boxing is far more universal and applicable to dynamic situations.
karate is far too structured.