For the Performance Model 3 they matched the 310 EPA rating of the RWD LR Model 3 already being sold.
The Model S P100D EPA rating is 315 miles vs. 335 miles for the P100D.
(IIRC the actual test rating for the RWD LR was something like 334 miles, but, Tesla choose to use the lower 310 figure... so, unclear exactly how the Performance Model 3 range compares to RWD LR.)