Not yet.
I am debating whether I will buy my Altima when the lease is up. I would really like a BMW but with our pension woes I may have to settle for the Altima. I say "settle" even though it is a really nice car.
You never buy the car after you've leased it. Ever.
If you're going to buy one, buy a separate one. But don't take the option on your lease to purchase your vehicle. It's a money losing move on the buyers part. Cash out the residual value and buy a separate one.
And as much as you like BMW, you better have money for the maintenance. They're terrible on maintenance and repair costs. If you want European performance , Audi is better in that regard.
If you do buy the BMW, get the service plan thrown in on it.