[MikeMidd]

Before you do anything -

First, read a lot about leases and what the different numbers mean. There is a whole new collection of terms to learn, like money factor, residual, down payment (or cap cost reduction) versus multiple security deposits, etc., that can affect, in a huge way, your total cost. For example, money factor is essentially your interest rate on the car, so just like you wouldn't purchase a car without knowing the interest rate, you shouldn't lease a car w/o knowing the MF. And do some thinking on how long a lease you want (24 mos? 36 mos?) and how many miles you need per year (keeping in mind that going over on miles will cost you).

I'd suggest test driving the convertible, the coupe and the sedan. They will all feel different, so get a sense of what you prefer to drive, what type of space you need (I mean, the E90 isn't "huge," so don't assume you are ready for a long road trip with 5 people with it). Then work from invoice prices on the cars, using a lease calculator to input all the different numbers and figure out what it will cost you for the monthly payment. But don't just work backward from a monthly payment, because dealers can always use that as a way to sneak things in or rip you off.