Motorstorm pacific rift getting fustrated....(ps3)?

i am on rank 7 and it is getting very very hard it's fustrating like i can some times complete the race with out wrecking and still not win each level is taking me ages to finally do and i have only done 2 levels in rank 7 and that took me about 2 hours it's not that i am crap at it because before i got to rank 7 i was winning everything quite easy and does motorstorm get harder and harder every rank? and also what happens after rank 8 is completed?