[dingaling]

It seems that once the S70 was released it was removed as an optional line-item across the range and was bundled into the final price. However owners of suitable non-S40 vehicles from before that point can still enable access for a fee ( they have the hardware already installed, it's a database flag change ).

"If your vehicle is eligible, the Supercharging upgrade option will be visible in the Available Upgrades section."

http://shop.teslamotors.com/products/enable-supercharging

The S40 has the hardware for Supercharging but is excluded by policy.

I'm only aware of this because a friend in the UK has been trying to work-out what's applicable in this market and Tesla's constant changes to the policy makes that difficult.