Best way to instantly get it is to just glitch your car into something.
I tried this, I just drove through the sign and the wall, but maybe I took the wrong car.OK, but:
Not any car: Premium Rally car.
P.S.: I tried the 140 sign on Monza, I could just pass it, so no quick way there.
Just banging the car in the protections of the first chicane does it after a few minutes.