Most importantly, if you want a clean engine, then you should at least use 95 RON fuel. There are other benefits I've experienced using 98 RON in my Aurion(my experiences can apply to you since the engines are the same), which are the fact that the engine runs more quietly ,the fuel economy relatively improves and hence more environmental friendly and as the others mentioned before me the throttle response and power sharpens as well. For about an extra $7 thereabouts per tank, the benefits are worth considering.