Not X5 related but ....

[sv1cec]

OK, I already have an X5 but I am planning to get a new (used) BMW next week, it's going to be either an X3 (3.0d, 2005, about 120,000 km) or an 320d, 330d (late 2005 or 2006), or a 530d.

My question is:

Since it is quite common for the sellers in the country I am buying from (Bulgaria) to alter the mileage shown on the dashboard, is there a way to check the real mileage of the car, using the well-known programs? If yes, which one and where do I check it?

Any advice will be greatly appreciated.