Quote:

In UK speedos have to over read by upto 10% when the car is new. They are not allowed to under read. All the cars I have driven in the UK over read by 10% or more.


It's a little bit different to that, but similar:
http://www.theyworkforyou.com/wrans/?id=2001-03-12a.59.3

The accuracy is usually the same across any make, I believe there are some manufacturers who supply vehicles which are pretty accurate.