Q:
A: Yes, absolutely. If you put in regular fuel, the car will still run. But the anti-knock sensors will work like mad to mitigate the damage to your engine. With regular fuel, there will be less power available to you, and the maximum RPM you can reach will be capped. While this may be fine for normal driving, in an emergency situation you may suddenly find yourself restricted. There are many reasons, including: 1) Higher compression engine means more power in a smaller engine, with better fuel consumption 2) Using premium gas allows for different catalytic converters and other emissions equipment, to reduce environmental harm. The TSX is a fabulous car. =]