I only use super premium plus. Not sure what octane it is since I think the German's use a different rating system. If you run low grade gas your PCM will recalibrate the boost to a low setting as a safeguard against knocks and pings I guess to prevent damage to your engine. I would recommend only using hig octane gas. It will take awhile for your omputer to reprogram and re-learn that you are using high octane, but your HP will return. Just my suggestion. I know it's expensive, but it's the only option for our picky cars.