Tesla Model X
The Tesla Motors' Model X will be available only in AWD versions and the top 90 kWh versions (90D, P90D and P90D called P90DL) at first.
The pricing has yet to be announced outside of initial Signature offerings, but we have already had multiple signals that the expected price for the Model X will be $5,000 above a comparable Model S.
As the Tesla Model X 90-series has already got EPA rating, we can compare X with S. There is however a catch, because Model S 90-series got rated strictly from 85-series data, despite 5 kWh more energy and expected up to 6% more range. We added about +5% range to corresponding 85 versions to be able to more accurately see range differences between S and X.
In our estimations, Model S 90D should be rated at ~283 miles on the EPA metric, while the Model X 90D is rated at 257 miles. The estimated difference is 26 miles (9.2% less), which is a testament to the aerodynamics of the new electric SUV.
In the case of Model S P90D/P90DL and Model X P90D/P90DL the difference is about 16 miles, or nearly 6%.
Interesting gain comes from Ludicrous mode - 0.6 seconds quicker accleration in the X (nearly 16% quicker to 60mph), while only 0.3 seconds in the S (nearly 10% quicker).
Tesla Model S/X comparison for U.S. - October 2015