I believe they are standard on the Dynamic only. They are an £1150 option on the Prestige SD4 models and not available on other Prestige models and Pure's. It's one of the trades - much less leather in a Dynamic than a Prestige, for example - and the two (Dynamic & Prestige) will appeal to different buyers. I'm going for the petrol dynamic.
The Dynamic is intended to provide a more sporting drive experience and I expect the dampers will provide more neutral cornering. Looking at the pictures on the Autocar web-site of the car cornering, the front dives and the car rolls on heavy cornering. It's never going to be a sports car but the dampers should help.
i will be inerested to hear if magnaride dampers improve the ride comfort on our third world roads. If I do buy an Evoque it will have the petrol engine, which means a Dynamic with magnaride as standard.