Im thinking about buying LFS, but im wondering, can I place objects in S1 license? Or this feature is only possible in S2?

You can do it with an S1 licence I believe.

If you are planning to race online, I suggest getting S2. I bought S1 just to see what it was like and there were barely any servers to join that I couldn't already join on the demo. Then I upgraded to S2 and it's totally worth it.

there are 0 servers for s1, mabey an empty one...

You can use any S2 server so long as it's only S1 content. For example, if the RSR server was on South City with the TBO's, you could go on that.

make sure you turn on "empty" servers too find more servers to join.

Thanks for your answers!