Lol guys i got the old one that was failed for some reason ogm but now its here i dont take any credit thoNo, I made a new one, that uses the function getcontrolobjectspeed() and it causes no lag, even on servers full of players and bricks.
It's obviously client sided, also.
It dosn't look (attached picture) all that great... but it works, and the little red needle goes from 0 to 75.
The blue thing will be a light which in a later version will tell you if you're going fast enough to die when you hit something.
Download:
http://www.mediafire.com/?j8nv548hcdj6zg6