[peterbrown77]

My Corolla is rock-solid on the speedo. I have an app for my Android called "GPS Essentials", lets you display everything GPS - altitude, average speed, max speed, min, instant, bla-bla-bla. It consistenly shows exactly what my dashboard says. On my 986, I am off 4 mph at 70, I've never checked if it is off by a percentage or an absolute number. Either way, it seems pretty piss-poor for an expensive car to be so wrong. I lock the cruise at 75 on a trip to keep the car at 71, which I figure is about where law enforcement starts to perk up its ears.