Great for everyday use.

I use this app every single day. I recently purchased a Nissan Skyline and the speedometer is in KPH. This app accurately tells me how fast I am going in MPH, as well as showing me lots of other interesting facts about my driving.
I liked it so much that I bought the full version!

Potatoezzililikaiaiajdhrbebejs about Speedometer Speed Box App, v7.0