Higher pack voltage would go a long ways at solving this.
We have to stop coming back to it being this easy, or this even being the best/economical way to make the car faster if you assume it's built on the Model 3 Highland platform.
First, Tesla Model 3 motors are already rated at 320V. There's no data that they can take advantage of higher voltages.
The Plaid motors are known to put out much more power in the same size package as Model 3 motor and keep it flat to very high RPM, even with only a bit more voltage. The Plaid motors and their very different magnetic design tell us that there is more too it than voltage.
We already know the Highland uses the same battery as before. So we know Tesla thinks 82kWh is reasonable for this platform. Tesla does this in a 96S46P pack. That's 4,416 cells.
Let's say we re-arrange these to the Plaid voltage- 110S. But we're not adding cells. So now we're 40P instead of 46P. We know the current pack does about 1300A, so a 40P would be limited to 1,130A.
Hmm, well our peak current just went down, since parallel cells get current (torque) and series gets voltage (RPM).
So how sure are you that 402V at 1,130A would be faster to 60 than 350V at 1,300A with the same motor?
Meanwhile, we know the Plaid motor can do something like 400HP flat rated to 200MPH on a 402V pack. Which logically means it could do 400HP flat rated to 170 MPH on a 350V pack. The trick is that it probably needs Amps to do this- which is why the plaid pack is 72P, although that's for 1000HP total. Well, let's re-arrange the Model 3 cells to be 72P, and now we have 61S, or about 225V. Arguably that would still flat rate 400HP to 110MPH.
And to point out just how well this math works out: Model 3 is about 1,300A on 46P. 1000HP is 737kW, which at 402V is 1,830A. 1300A / 46P = 28A per cell. 1830 / 72P = 26A per cell. Tesla is clearly loading each cell at peak about 100W per cell, and there's no free lunch.
The only point here is that the Plaid motors use volts and amps differently that other Model 3 motors, and it's not perfectly clear what would make a Model 3 faster on the same number of cells, and it might be more current, not more voltage, and that I bet a plaid rotor means a lot more to the car than a different battery voltage, and a plaid rotor is WAY cheaper to do in low volumes than a different battery pack. Hence the reason the 2021+ Model S/X all have identical battery packs, but different motors. That makes much more sense for the M3P as well, and given we've already seen different motor numbers for the M3P, but no data on a new battery PN, I'm pretty sure this is the way Tesla is going.