unreal tournament 2004

[SuperGenius]

i've played the demo, and want to buy the full version BUT

i don't get what the real difference is between the plain version, editors choice, goty, etc. and if the differences in price are worth it.

what got me excited about the game was the user maps and the like. I gather that it includes a map editor, but does it unclude a way to make custom vehicles like i've seen in the forums?

and what of the security of these user created additions? is it possible that they could corrupt your install of the game or even the entire systen?