No RWDs were uncorked.
Pre and Post July 2017 RWD performance involves a couple things: an increase in torque (50%), an increase in max power (20%) and an increase in battery current (15%). Although the torque increase could theoretically be done to the new drive unit, it was also done to the old drive unit on the AWD cars. The latter two, Max Power and Current increase seem to be battery dependent. Unfortunately uncorking was all or nothing.
Also, is your battery upgradable to 75? Even on the AWD the car would have had to be upgradable and upgraded for them to attempt it.