It is theoretically possible that I could increase the acceleration of this car significantly... perhaps matching or maybe even beyond performance of a P100D. The limiting factor of this particular car: max torque.
650 Nm is the most torque possible to output with Tesla's firmware as it stands. So in the P90++ the whole system is torque limited until about 50 MPH. Torque remains at a constant 650 Nm until then. Then, the system is current limited at a bit over 1400A. Then, the inverter becomes thermal limited after a short time and tapers current.
Interestingly, this car's improvement in 0-60 time vs the P85 is almost entirely due to the higher max sustained torque (650 vs 600 Nm IIRC), and that it can sustain max torque for over a full second longer than the P85 due to the higher current limit.
Overall, though, the torque limited period is the longest, lasting about 2.6 seconds after a launch. Torque ramp from 0 to 650 Nm only takes about 0.15 seconds... which shows that better tires wont really help me significantly. Interestingly enough, torque is at full before the car travels past the 1-ft rollout mark.
Now, I can up the torque... but the consequences of doing so would likely be damaging. Sustaining 650 Nm for several seconds is already a pretty significant strain on the system, but within reasonable limits. If I bump it more then we're looking at damaging or otherwise accelerating wear on the axles, hubs, differential, and possibly even the rotor spline.
*shrugs*