I've only caught a few so far.
1. Shen Zen outift - Bruce Lee in many movies, but I think Fist of Fury in particular.
2. Hog Pen Row outfit - Stephen Chow in Kung Fu Hustle (The outfit is named after Pig Sty Slum). That whole "discover your inner genius" description is because that is exactly what happens in the movie.
3. The Bon Gak outfit - Ong Bak. This outfit should have made all of your kicks break bones. :)
4. Manhattan Melee outfit - Jackie Chan's outfit in Rumble in the Bronx. Fun fact, Jackie Chan broke his foot in a stunt near the end of the movie, but wanted to continue, so they put a cover over his cast to make it look like a shoe. Wei Shen is wearing an identical pair of shoes.
I also heard that there are some Just Cause references, one in the form of an outfit and another in a radio commercial.