As all you know this race system can give you a race which is long and boring. I think that is time for changes. In old one u can get long races like Ambassador Ridge with 2-3 laps in stock manana, which i think is kinda boring. I came up with my new race system.
For low score cars like under 200 will be a limit to 3km per race. (Every + 50 score + 2km for race limit) 250 score, 5km, 300 score, 7km and so on to 500 score. But it doesn't means that Manana 199 can race only this 3km races, in each score there can be a shorter races but not in opposite way .Of course its only for quick races, not for custom races.
I think it would be good for new players which want the fast gameplay and for older players too.