Im looking for some help and not sure where to go.

like how to change the tyre options that are available like in bf3 makin the dirt tyres available, and it tells me that some setups arent suitable. how do i change that.

just another question as an admin can i get myself into a s2 car then set the server to say bf3 and only the xfg and xrg available, will it still run as a demo even tho im not in that type of car. say if i was in teh fz50 or ufr.