Is anyone driving with left foot on brake during harsh event like auto-cross or rally? I heel-toe a lot but at one point last weekend I was curious if setting the car a little with the brakes while keeping the power on would have been a good move. I'll have to read up a bit and see what the experts are doing.
Drop the throttle and it will stop under-steering real quick. Just be careful where you do this.
Left-foot braking is faster, but only if:
1) you have the sensitivity in your left foot to modulate the brakes effectively.
2) you do not need to use the clutch to shift.
Assuming the Elise has a full-synchro gearbox, you need to use the clutch, and that precludes left-foot braking in any corner where a downshift is required. But nobody downshifts on an auto-cross course (just short-shift off the line and take the whole thing in second), so it could work well there. Even on a fast course where 3rd is required, it's difficult to imagine you'd downshift more than once. Heel-toe for that corner, and left-foot brake everywhere else.
Now, if you're used to right-foot braking, your left foot may not be sensitive enough.
The point of left-foot braking is mainly that you have a quicker transition between acceleration and braking. Coasting is not what you want. Especially with a rear weight bias. It's okay to be off-throttle for a bit, to help rotate the car. This is the advantage of a rear weight bias. You can turn quicker, and earlier. Pick up the throttle earlier than you would in an FR car, though. It's all in the timing.