I think your logic is completely flawed here. If your budget is 30k then you should be looking at the best deal for that amount. The best deal would be a 2012 Nissan Tiida/Toyota Corolla/Mistubishi Lancer with a mileage not exceeding 50k. But a 2004 BMW X3 or a 2003 VW Touareg with a mileage above 150k is a complete waste of money. Starting from a certain age and mileage, many of the elements in the car die or reach their last moments.

If you are insisting on a German brand, with 30k you will be able to buy a clean 2010 VW Jetta