BMW will be replaced with..

[Rylund]

Can you explain part about "You will be able to exchange it" Does it mean there will be option to simply swap cars or something?

Imagine if just bought the BMW because you wanted to have the most expensive car. Now the car will be removed from Market. You can swap the car with the new one or keep it. If you keep it, it won't be dropable. You can still sell it for 50% of the market price. This is to prevent prices such as 5 million because the car became legacy.

can you still own both the new car and the BMW?

If you choose to keep the BMW you can still purchase the new vehicle. 
Swapping is just an offer for people who don't want to keep the BMW, and instead they will be given the new car.