You're calculating the VA tax wrong. In VA the car tax is added to the negotiated price. So in your calculations, multiply the negotiated price by "1.0317". Then use this figure in your calculations. In VA the car tax is due up front and is not spread out in payments. Either you can pay the taxes up front out of your pocket or borrow more from BMWFS to cover the taxes and roll that into the lease. So in your case you can either give the dealer ~$1300 in taxes or borrow $1300 from BMWFS, which will be added to your "Cap cost" of the lease.
I hope this helps. I can give you some spreadsheets if you like. Just PM me.
Give your dealer a call and ask him to fax you a break down of the numbers.
On a side note, have you visited Passport BMW? Thats where I got my 335i and they gave me an excellent price. If you want, PM and I will give more info on the SA that helped me.
Good Luck
