JSGME mod manager.
Run the exe, select the 'install' to your /Codemasters/F1 2011 or /Steamapps/Common/F1 2011 directory, create desktop shortcut, a popup will apppear asking you to name your mod folder (default its "MODS") and you simply put the file(s) inside the MODS folder, creating a main folder to name the mod so you know what it is on the mod manager.
For example you would put the "cars" folder inside a folder you name, such as "[RDDev] T-Cams" inside the MODS folder.
Then run the shortcut you added to your desktop, on the left it will say "[RDDev] T-Cams", simply click that, then the add arrow to install, and click it on the right then the remove arrow to uninstall.
Download link:
http://www.users.on.net/~jscones/software/products/jsgme_setup.exe