I like this time attack, it's to my understanding that when you attack the car it speeds up. Therefore if you space out your kicks, you'll be able to get a lower time than you normally do. What makes this tricky is that you have to clear the way for the vehicle, while at the same time not venturing off so far that you can't get in an adequate amount of kicks. There could be other means to get the car to go even faster, but I'm not aware of it at the moment.