Yes, it is possible but you need to have separate 360's, tv's and games.
You cannot, GTA SA has a much lower graphic system then GTA IV, plus the cars in GTA IV have more addons than GTA SA.
u can use htem in multiplayer
No
ya
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.
Yes you can.
No... It is GTA 4!
use gta4.net's interactive map
You cannot get use airplanes, you can only use helicopters.
There is no cheat. but if u have wifi or internet on your system you can mod it
They disappear as you go through the story, of GTA IV. See the related link for more information.
but other cars uses the indicators how? but why we cant use the indicators