BMW Financial services is very good, I didn't even bother with the banks.
I bought a 335 in July 13, got approved no problem with a balloon payment and prime less 1%. Now you think I'm crazy for buying with a balloon? Well my car was only supposed to come in Sep, but dealer found me 1 within 24hours and the buyer of my Double Cab wasn't ready, he paid me off over 3 months, so once I got the 1st installment I settled the balloon plus some capital, kept my installment the same so my period was shortened by a year. Best part is you keep the negotiated interest rate.
Bearing in mind I'm a self employed accountant and treated as a 2nd class citizen because of the New Credit Act, BMW FS was very good and gave me no crap, even when I settled the capital, finance was approved in about 30mins.
So a tip, if you have a deposit don't put down Upfront, as you negotiate a better rate, then after a month or 2 pump in the deposit, you will keep the interest rate, then you can decide to keep the installment unchanged reducing the period or keep the period unchanged but reducing the installment.
Another benefit is that if you have a vehicle financed through BMW FS, you can also apply for a Homeloan through them.
Good Luck, now you must find your perfect car