PM8 Peer comparison - Other REE projects analysis, page-229

So, as you know, our Model 3 has a permanent magnet machine now. This is because for the specification of the performance and efficiency, the permanent magnet machine better solved our cost minimization function, and it was optimal for the range and performance target.

Quantitatively, the difference is what drives the future of the machine, and it’s a tradeoff between motor cost, range and battery cost that is determining which technology will be used in the future.

From Tesla's chief engineer Konstantinos Laskaris