FINISH THE CAREER MODE BEFORE BUYING DLCs !!
The DLCs are fine but buying them will literally RUIN the Carrer mode bc the devs had the absolute braindead idea of instantly giving you 2.500.000 credits and 36 new cars with no way to refuse or wait after career is over... So you'll basically own every car in the game and be so obsecenely rich that it totally defeats the purpose of the career mode. So yeah, first finish the career mode, and then buy those DLCs !