Ok guys, that expansion doesn't effect anything beyond 2% (moderate) -5% (extreme). So technically speaking you might be spending 2-5 dirham extra per 100 dirham tank. baah. HOWEVER, do you know that all petrol station have their storage tanks atleast 6-10 feet below the ground, that keeps them lot cooler even in the hottest day and I have personally touch the petrol while filling up the quad and it was so hot to burn my finger, it was reasonably slightly more than a room temperature in 30's. Go check by yourself and touch few drops before believing anyone around with theoretical knowledge.
To be honest, with so many reforms happening in Dubai to make money and grow economy to make it more sustainable I don't think this is very far off in the future. Especially before 2020, govt will defintely try to make a balanced and health economy, come what may requires: taxes, vat, toll etc. Bottom line: Enjoy your dream car as soon as you can before it becomes more difficult to afford