This is exactly the issue we're trying to work around. Many managers have done just as you suggest and given up running two cars because of the costs. As a result a great deal of the competitive 2 car leagues have disappeared.
It's easy to manage if you only race a couple of times a week, the daily rewards and Ads allow you to keep your head above water, but daily two car racing has become unmanageable unless you either spend real money or exploit the system and farm game money and parts in a one car league. If you do this you run a real risk of having your account closed down.
Bruno's suggestions make a lot of sense and are very much along the same lines as I was suggesting on the volunteer server not long after the Level 30 update dropped and I was forced to abandon my well established 2 car league because most managers switched format.
As for making management more tricky, I agree. It may be an unpopular opinion but I think one car resource management needs to be made significantly harder to put a stop to the exploit I mention above.
