I've heard that the optimal launch for the Tesla is to press the brake and the accelerator at the same time. Then suddenly release the brake.
While the motor doesn't rev up, it does torque up, making a faster launch. I think that's how you get the 4.0, or 4.1, or 3.9, or whatever it is now.
You also need have a full charge, put it in performance mode, and then drive enough for the batteries to warm up, but not so much that the motor or PEM overheats.