#Franco :
usually when a car makes the game crash, leaves a comment in the error.log file in the main game directory, but sometimes it can leave nothing....
maps go in the \maps\Addon_Maps folder (both data folder and .rpk file)
garages are different, they replace slrr garage files in the misc folder
okay thanks ill get back to you when i get home and see what it says. and as for the maps sometimes it has the folder .rpk and then another file thats like rbg or whatever its called