Well in F1 2010 I used 3 different installation folders with no problem, similar to what ML2166 does now. Just try it out for yourself.
Go to your Codemasters folder, copy the F1 2011 folder, then immediately paste it back down in the Codemasters folder. You will end up with a folder called Copy of F1 2011. Now rename the folder to something more preferable, enter the folder and create a new shortcut to the f1_2011.exe file .....
Regarding online stuff, in F1 2010 I remember starting the wrong version of the game (heavily modified), to race a few friends. I am not sure now, but I was either prevented from joining the lobby, or prevented from joining the race. Either way, no harm done, I just rebooted the game from my (lightly modified) game folder, which just had visual mods installed (camera, fov, car textures, helmet textures etc.)
EDIT: Just as test, I have just quickly started up my game from my backup folder, on a totally separate drive (it was copied and pasted there just after I installed the game). Everything starts just fine, all the settings are there, just as ML2166 say above .....