All S/X 60/60D refresh cars (around May 2016) are actually equipped with a 75 kWh battery pack. You can upgrade the functional use of the pack to 75 kWh for a one-time $2,000 fee (the cost 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. (Feb-2023 update)
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 Tesla service to see if it might still be available.