I was able to reach it with 4 Class D cars, two of them heavily upgraded and just 2 Class C cars, one of them fully upgraded to parts Level 8, so it will be easy to reach to however plays actively the game, even with just the campaign. The main purpose of the Level 5 means that better class blueprint cards are unlocked.
In Garage Level 5 are from these cars:
- Class B: Ferrari 488 GTB
- Class S: Lamborghini Centenaro
- Class C: H2 Speed
- Class A: Dodge Viper GTS