true, true... almost all speedometers have diff readings, some even off by as much as 15%!
best proof of all for your speed is by hitting max velocity at places along the known path where speed trap cams are located. When they send you summons, you can PROUDLY scan them and post here!
But from my experience, it is only 179km/h being recorded. If beyond that, somehow I have not received any. It is always the same phenomenon, see the camera, brake like shit, then snap... your proud speed of 120-179km/h is being recorded via you driving it! Wow! You cant get this anywhere else...
Hahaha! RM300 is the max, RM150 is the norm - worth paying to be acknowledged of your achievement, aka as speed. Better than dyno, because on the road, the wind and aero drag has been taken into account. In other words, that is the true speed.... with date and time in case you did not notice it.
Of course, you can save up by using GPS... not as thrilling though. What is the point doing 300km/h when you do not get to live to tell? Even if you do, what is that to be proud of? Until today, I am still in search of that answer.... must be the motoring blood i received during my last operation when I had my EVO MR totalled - oh, that was like 5 years ago.... no, I am still a speed freak. If you spot me along the highway, give me a flash. That might slow me down, thinking there is a speed trap up ahead.... hehhe, but on second thoughts, I may gear up the speed, hoping to be photographed for the next summon... catch me if you can syndrome.... sigh