YOUR experience is normal, not only for the Monaro, but for other high-performance models from Holden. It's a combination of the car's suspension geometry, tyre size and profile, road surface, the speeds you do and the pressures you use. Tyre experts are unable to offer an alternative tyre that will give you better mileage. All they can suggest is that you rotate your tyres religiously, and maintain pressures to the correct specification. Perhaps you can run slightly higher pressures if you regularly travel at highway speed.

SOUNDS like rubbish to me, too. Your car clearly has a problem. Take it to an auto-electrician and get them to check it.