If the Taycan does better in EPA rating than about 36kWh/100 mi ( Model S P100D does about 35kWh/100mi), I would say that Porsche is doing well, and that shows they have a close-to-competitive-efficiency drivetrain. That would give it 260mi EPA range, assuming the same size 95kWh battery and they do the same battery limiting as in the e-tron (I think this is about the same (slightly less) EPA range as the P3D+ would get, if they tested it).
It's true we might not see those official numbers for a while...