Speedometer

[Staffanlind]

What do you mean by that? If your tire size and tire rolling matches to installed tires, it should show you the exact speed. 
I tested my speedometer with my pro-GPS (not car's and not phone) and it always shows the same speed what car's speedometer shows!

Not mine, not in this car and not in any of my v70 and not in any car i have had. Maybe it's because market. I live in Sweden and here, as far i know, all car not show real speed, it's about 3-5 km/h to little, my is 5 km/h.