2010 118TSI just been for 60k service. The car shudders (mildly) on start-up for about 20 seconds and have been advised by the service guys to run on 98RON. Have always run on 95 and the cap says 91/95. Also have read on various forums that running a car with a 91/95 spec on 98 will give no advantage on consumption or performance. So question is why are the service guys recommending 98? Should ask them should I not but would appreciate your thoughts too.