EPA mileage ratings were 18/26, but like Larry said, it's very dependent on your driving habits and style.

I find high teens to low twenties around town depending on how much is freeway jaunts and mid to high twenties on a road trip. A long time ago I got one freeway leg at a little over 30, but that was pre-oxygenated fuel, which had about 3 percent more energy content which is about one MPG.

Short trips in urban traffic will yield the worst mileage. Long trips at or below the speed limit will yield the best mileage.

I also run regular unleaded, but since I only use my 190 during the winter months when temperatures are cool, it only occasionally exhibits a little transient detonation with my normal short shifting driving style when it's warm. In that case I just rev it a little higher in each gear.

During hot summer weather at least mid-grade if not premium will probably be required to keep it out of significant detonation.

Duke