I have always run my S3 on super unleaded (97 RON) but last weekend i filled it up for the first time with shell v power which is 100 RON here in Switzerland. Anyway after about a third of the tank was used the engine management light came on. Is this just a coincidence or could it be related to the sudden jump in octane levels. The tank was very close to empty and i filled it right up so its hardly dilluted at all with 97 RON. The car is still running fine, although i have been keeping off boost as much as possible since the light came on.