To get mods you would have to JTAG your xbox which Microsoft will find illegal since you can pirate all types of material and you will probably be caught and banned if you have xboxlive.
Gta 4 on xbox360 monster truck cheats
You can't. Mods.
I have it for ps3 and xbox360
fileplanet
hotswap
Yes.
Various websites. Try typing gta iv mods for ps3,xbox(etc.etc.)
actually you have to buy the mods once you buy the one you wont its free.
For example with GTA IV, you can modify these files: vehicles.ide, vehicles.img, carcols.dat and handling.dat. that are found in the directory. Just search for "GTA IV PC mods cars" in Google and you will find some fantastic tutorials..
gta IV will only be for Playstation3,Xbox360 and PC
There is no cheat, however if you own a pc version of GTA IV, then you could use a mod, try gtagaming.com for this and many more GTA mods.
Why wouldn't it? I assume you are talking about GTA IV