Merry (belated) Christmas, owners of the recently-released Grand Theft Auto III on iOS and Android. That mobile version you bought is actually, in almost every respect, the old PC version of the original, meaning if you can get at its file structure, you can use PC mods on it.
For Android users it's as easy as going to your Android/Data/com.rockstar.gta3/files/GTA3 directory, while iOS users may need to get a little trickier (or have a jailbroken unit).
This isn't a complicated workaround; because this is essentially the PC code running on a phone, you just find PC mods and drop them in the right directory and they should work, same as they would on a computer.
Unexpected bonus: Grand Theft Auto III for Android and iOS can be easily modded [The Verge]