Couple of quick points. You can get a 2010 at about 500 under invoice. So you should be able to get a better deal on a 2009. There are some threads on this as well.
As for your rates, you can get AAA in my region at 3.09% and there is another thread on how AK scored 3.99% and invoice. On what you would need to do to get "military" rates.
How I have scored invoice pricing with 3.99% APR on my 370Z?