Suggest you check out the gtawiki site which has a comprehensive list of just about everything on GTA games, including cheats and mods. Just use their "search" to find the section required:
gta.wikia.com
gta4.net has them and some (most really) are super fast bikes, cars, and a heli i believe as well as wanted down, and health
my name is Micheal there are 2 million
4
gta iv cheats xox360
no.
No,but there are normal.
No
no
There is no Ferrari in GTA IV. There is a car called the Turismo wich is based on the Ferrari 360
nope
yes go on cheats then its there
http://www.gtaivcheats.net/ include gta iv * 360 Cheats * PS3 Cheats
There are cheats to do that.You can just drive to the other cities by crossing bridges.
It should do that automatically
no is doesnt ruin your game. but some cheats block soms achievements