Are you going to be present the hole time or absent to do other things while its racing.
If your Present using a x2010 on the very first event race. (boring as hell)
If absent then Dream car race for 20 mins followed by 4Hr endurance races when going to out.
This is realy slow bar to level up unlike B-spec level bar that jumps multi levels per race.
Multi races are need to get any increase in the Bar een if you use endurance races.