@Tuoyo
The main problem with the R3 cars and forward is that their inital Torque is too high. Without TCS on, you'll probably spin the wheels for too long, until you hit second shift. Use soft throttle impulses or don't start in full throttle at the beginning of the race.
About the Class skipping, it's natural, since you began doing a E class championship, then C class, A class and now R3 class. The other class championships are on the Event List, you can race them anytime.
Current PC Build
CPU - i7 8700K 3.7 GHz (4.7 GHz turbo) 6 cores OC'd to 5.2 GHz with Watercooling (Hydro Series H110i) | MB - Gigabyte Z370 HD3P ATX | Gigabyte GTX 1080ti Gaming OC BLACK 11G (1657 MHz Boost Core / 11010 MHz Memory) | RAM - Corsair DIMM 32GB DDR4, 2400 MHz | PSU - Corsair CX650M (80+ Bronze) 650W | Audio - Asus Essence STX II 7.1 | Monitor - Samsung U28E590D 4K UHD, Freesync, 1 ms, 60 Hz, 28"