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I used: GPS Speedometer because it was the only one that offered a white background.
I also used DigiHUD and found the same thing but only around 66kph (it was too dark so I pulled over and found the first one so i could test at 100 ^^^130 and read it with a quick glance.
Lead up:
Before I had the tank bag / app I did notice that traffic was crazy fast, I'd merge in and even the slow lane was 10 over... I figured it was just a good ride but then i pulled up beside a Civic and found that his HUD said ~120 and mine said ~130...)