And of course I forgot something.
Group R:
R1A: up to 1400 cm3
R1B: over 1400 cm3 and up to 1600 cm3
R2B: over 1400 cm3 and up to 1600 cm3
R2C: over 1600 cm3 and up to 2000 cm3
R3C: over 1600 cm3 and up to 2000 cm3
R3T: up to 1600 cm3 (turbo)
R3D: up to 2000 cm3 (diesel)
R2B:
Skoda Fabia