What I have found, and I have always suspected since checking this lease business, is that it does not matter what your residual value is. Of course, the company is not going to tell you that...
I just finished a lease on an Isuzu Trooper. Without even asking, they offer me to sell me the car for $5000 less than the residual value... by phone!. Yes, this vehicle is very poor in resale value, but if you think about it, all vehicles out of a lease are used vehicles. Somebody will buy them, and not necesarily at some sticker price. This price will be negotiated. Therefore, why you would pay the residual value (look at it as a new MSRP) for an used vehicle? I never will pay MSRP for a new vehicle, much less for an used one. But that is what the leasing companies want you to do.
If you check the resale value of any 3 series after three years it fluctuates around 60-65%. The residual value attached to my car is 60%. Although my downpayment is towards cost capitalization and not towards the value of the car, at the end of three years, everything being equal and the car condition being excellent, I should have around $5000 in 'value' for the next car. This is taking into consideration that this residual value will be negotiated.
Although I put a considerable downpayment on this lease, the reality is that I was going to pay more in the long run compared with putting a down payment now. For the $7000 in downpayment that I paid upfront, I saved $500 in the long run in payments. Plus I saved another $455.00 in taxes... In other words, with no downpayment I was going to end up paying almost $8000 in higher monthly payments and taxes.
But remember, certain conditions will have to be met for this to happen to me. I would have to lease another BMW (no brainer), I should stay in the same price bracket and deal with the same dealership among other intangibles. And most important, BMW will want to do business with me again, be this car or a new one. . Most probably I will not be able to achieve all my number goals, but I will be close.
Remember, you are dealing with used cars. No more and, certainly, no less.
Anyway, you should try and see for yourself. Do the math and negotiate.
Good luck.