In Manafacturer battles you will go up against cars made by what ever manafacturer you have chosen to go up against. You can only race cars that are the same manafacturer as the event you are choosing to do. example, you cant do the Nissan event with a Mitsubishi but you can do the Toyota event with a Toyota. This is the only way you can get Rims outside of events.

Manafacturer Reward
Honda Watanabe STELLAR Gunmetal Silver
Mazda ENKEI Racing RS+M 
Mitsubishi  ENKEI Racing JS+M
Nissan RAYS VR GT-TypeC 
Subaru Watanabe GR-8 Silver


Each Round goes for 10 races. Races 0-4 and 6-8 of each round you get Nitrous tanks as rewards. At race 5 the opponent is enhanced and you get a S-tank as a reward. At race 9 the opponent is further enhanced and uses 3 tanks of Nos and you get a order ticket as a reward