I believe LFS is a game you never can learn fully. There is always new things to try out and learn, such as new driving style, new driving techniques, new setups, and so on. With a bunch of new cars and tracks (and even more with custom classes on Airio servers), it should keep you busy for quite a while to say the least.
I have never spent as much time on a computer game than I have with S2. Money well spent I'd say.