I think the exp is doubled as well as the cr at the moment on the seasonals because of Christmas and New Year. It might be twice as fast as normal in that case.
i start with 2x 2j races at cote from 0 xp to lev 22/23 then move to sazuka with a speed 8 without zonda and and bmw gtr in race (after lev 34 ish the zonda really isn't a problem either) you can start and forget