From LFS Team:
Live for Speed is a serious racing simulator. No arcade modes, no steering aids - YOU have to do the driving. It is therefore highly recommended to drive the sim with a steering wheel, because even though you can use keyboard and/or mouse, a wheel is what you use in a real car, so a wheel should be used in a serious racing simulator. Especially when going online, where fast reactions are required.
In S2 you can race alone or against the AI, but the real fun is to be found online, in multiplayer mode. Racing against real people is simply the best thing and LFS makes it easy for you to do so. There are also several online racing leagues you can take part in, if you are looking for something with a more competitive edge.