Since you would be required to "payoff" your lease with the trade-in value of your 535 the large down payment would help in keeping your out of pocket costs to trade lower. Unless you absolutely need to get an X5 you'll be MUCH better off financially to keep what you have. If you got a stellar deal on your 5 you might be able to use one of the lease swapping services to get out of it. Did you apply the $7K to cap costs or to the MSDs? If you applied it to MSD my understanding is that the person assuming the lease will get the money in the end. This will make your car very attractive to assume but of course you'll loose the money.