There are a number of character specific icons and titles which are unlocked by clearing Arcade mode and through each character's unique set of trials.
Only for Ryu, Cammy, Chun-Li, Seth, C.Viper, and Guile: Hold the all kick button as soon as you see "Now! Fight your Rival!" to fight against the character's second rival.
Play arcade mode on Medium or higher difficulty in standard best of 3. Win at least 1 perfect match (Do not get hit either round), and do not continue. Akuma will challenge you after the final battle with Seth.
Beat the car bonus stage with Guy or Cody and the lower level baddie Bred, from final fight, will pop into the scene and cry "OH MY CAR!" just like in Final Fight.
For each match you use a character on, you will unlock a new color (#s 3-10) and Personal Action or Taunt (#s 2-10). Colors #1 and 2 are available from the start.