Both the Android and iOS editions of Grand Theft Auto III support user mods originally made for PC, cunning players have discovered. It's a bit wonky, but people have had luck bringing in new cars, textures, songs, and more.
Certain mods don't entirely work, suffering graphical glitches, but such is the nature of experimentation. If you're looking for mods to try out, GTA Garage is full of 'em.
Here's the Android edition with a few custom textures and cars: