To answer the OPs question, if your credit is excellent you can get loans through MBUSA or a credit union for 1.9% which is about $440/mo for 60 months. I've used Penfed previously and they were great, however, it looks like their rate is now 2.99% for 60 months.

 

FWIW I financed my TV as well.

 

I would say the minimum at signing is what you would want to put down.
Now like I said you still can use the multiple security deposits in order to reduce your interest rate. The advantage against the down payment is you can get that money back at the end of the lease or if the car is totaled. Which is not the case for a down payment.
What you need to understand is that a large down payment on a lease is money wasted since you will never own the car as opposed to finance.
As for the insurance if you have a comprehensive one already it shouldn't change with a lease. But yes leases require a minimum level of coverage.

 

why are you even in the c63 section. do you own a c63?