To be fast at autocross, one must be smooth with the driver inputs. Left foot braking allows one to modulate throttle on\brake off or brake on\throttle off at the same time for a smoother transition without surprising the tires.
I started autocrossing with an automatic and left foot braking, after installing the T56 it only took me 2-3 runs to get to where I could shift to second after the start then place my foot where I needed it for left foot braking during the run.
Where I did have trouble was the first time I ran a Speed Stop competition. First two runs I slid into the box, left foot on the brake...killing the engine in the process. Next two runs I tried to right foot brake through the 180 and 3 cone slalom but couldn't make it smooth...so I started to left foot brake through the turns...then just lifted my left leg in the air and got it ready for the clutch as I entered into the braking area for the box.
You just do whatever it takes to get er done...
