Ok guys, the poster did not ask for your two cents concerning financial advice. The poster asked about leasing.
You wouldn't be comfortable with $782 per month on an income of 75k - 90k; well maybe you don't have a budget. That is $9384 per year. Maybe the poster forgoes eating out and rather spend it on a BMW. In addition, the poster stated that he or she brought a Benz with cash previously. Let's just focus on the question at hand rather than give advice on what someone can or cannot afford.
Now back to the original post, yes the payment is too high even if you could afford it. I pay $588 per month, 39 month lease, 12000 miles per year, and my vehicle was $51k. As far as what to bring, as long as you have a credit score above 650 and have a good auto loan/lease history, than you will be approved. BMW will look at your auto enhanced credit score which will be based on your auto history. The auto enhanced credit score is usually much higher than your fico, all considering you've never been late on an auto loan or lease and have purchased vehicles in the past. They won't ask for proof of income unless something on your report gives them a reason to ask. The only time I ever had to provide proof of income was when I was 19 and brought my first car. I'm 34 now and have purchased 7 cars since.
Getting approved will not be your problem, getting the number right is what you need to focus on. I would suggest you take your lease numbers and post them to the "Ask a Dealer" forum on bimmerfest. It's under the section
The Best of Bimmerfest. You will find better answers to your question there.
There is another current thread on here where someone is leasing a 435 (selling price of $53k, MSRP $59k) and he is leasing in the mid $600 range. Even with $2k out of pocket. Huge delta between his leasing price and yours. That should say something.
FWIW I have higher income and much higher credit rating. I wouldn't be comfortable paying that much for a lease even though I know I would be approved. Just because you might get approved doesn't mean it's the best thing to do.
Reminds me of the mortgage crisis. Not that I don't blame the bankers a great deal, at some point people just need to have common sense when it comes to their finances. My two cents anyway. You can't say you didn't ask.