Different cars are able to start much faster with manual transmission under certain circumstances. Generally, cars start much faster if you hold accelerate and brake at the same time and shift up a particular number of gears once the countdown is over and then release the brake. In particular, all three class 3 cars (Age Abeille, Lizard Bayonet, and Assoluto Fatalita) can go up to max gear and max speed almost immediately this way. An example of this can be seen here: