How to mod on GTA TBoGT (PS3)?

Ok i have been wondering how i can mod my PS3 GTA or maybe any games. Now dont tell me you cant because i am friends with modders, my clan are all modded to level 10 because he wen in our game and made Money just go up by thousands within 10 seconds. I also met somebody in a freemode that was driving an invincible bladeless blue/green annihilator. So please tell me what i must use (USB, PC) or whatever to mod.