Retrofit the Twin Charger to get up to 58 miles of range per hour of charging. This has no effect on Supercharging but can speed charging with an HPWC or a high power J1772 charger.
The cost is $2,000 and includes both parts and labor. It is only available on the pre-refresh version of the Model S (cars made prior to April 2016).
The twin charger is out of production and may no longer be sold by Tesla. Check with service for the latest availability and costs.
Actually, it is now $2000 including installation
Thanks – I’ve updated the price.