If you can't do this early fear not, some of the events are hard even with fully upgraded favourite car so you can just try get 1 star on especially tough ones and once you get gold trophy on given championship Finale you can use ANY CAR to "tick off" it's events, even the ones from higher class. I used Apex GT 86 (street) to master drift events and McHandful (Supercars) for everything else.
Also Boing Wheels let you use many shortcuts and skiping large amount of lap on some tracks making some events really easy (example from 'Can Ya Dig It?' route B below.
http://bit.ly/2uImttb