I'm on the Tesla site and configuring a custom Model X for UK. I want to customise the estimated petrol and tax savings over 5 years under the Cash Price tab. But it doesn't seem to work. It shows -£7,000 at the start but if I enter 8,000 miles and £1.35 per ltr of fuel it gives me a saving of only -£500. If I increase the miles to something stupid like 36,000 miles, it actually gives me a cost penalty of £1,900!!! This is going to put EVERY SINGLE BUYER IN THE UK off purchasing as soon as they try to customise these variables for their driving habits. Also what's the petrol car economy based on? For clarity, I am using latest version of Mac os X with Safari.