"Big fan of yours" is correct form, "of you" is not natural English.
To say that there´s only one fan one could say "I am your big fan", if the person is supposed to have more than one fan than "I am a big fan of yours".
I met that friend of yours, Harry.
Eu conheci aquele amigo seu, o Harry.
(I assume that you have several friends, Harry being one of them).
That is not to say that you will ban the form "I met your Friend Fred".
Now I am not with my head around the fact that you have or are supposed to have several friends. I just singled out Harry.
I like that sister of yours.
(it assumes that you have more than one sister)
I like your sister.
You may or may not have more than one sister, but if you have only one then I can´t use "of yours".
I hope it helps and you have got the idea.
Grammar points aside, it´s obvious that someone using the language "daz streets" could use the way they choose, be prepared to listen pretty much everything with music, some movies depicting some ´hoods, etc.