All S/X 60/60D cars with the new refresh (around May 2016) are actually equipped with a 75 kW battery. You can upgrade the functional use of the battery to 75 kW for a one-time $2,000 fee (was $9,000 prior to 13-Jan-2017). This increases the range of an S60 from 210 to 249 miles. The S60D changes from 218 to 259 miles.
This upgrade is done in software and does not require a service visit.
As of 2019, Tesla appears to have discontinued this program. You’ll have to contact service to see if it might still be available.