Euro is getting stronger. US pay less for cars already compared the EU/UK. I bet the prices should have gone up more than they have but BMW will absorb as much as they can. Their margin will be hit but they are already producing 30% less cars due to less demand. In recession margin is king. Less cars sold means you need more profit per unit.
Get used to price increases. The economy is shit all round the world but it doesn't stop costs going up for manufacturers of all goods.