A code snippet discovered on the Tesla site suggests the Model 3 could achieve 0.237 kwh/mile.
If this is correct then the Model 3 will be one of the most efficient EVs on the market. This also works out to a 316 mile range for the 75kwh pack. And over 250 miles for a 60 kwh pack. I still think they may use a 55 kwh for the base, which still works out to 232 miles.