In house
Pro: lower downpayment with lots of freebies
Con: higher monthly due to higher interest rate

Thru bank financing of your preferred bank
Pro: lower monthly due
Con: less freebies, and higher downpayment

Best move is to go the any mitsu dealership and inquire about the 2012 model and what are the differences compared to the 2011 model. By this time the SA of any dealership were already informed of the upgrades done to the 2012 model. Placing a reaer ation doesnt means you are already tied up in dealing with the dealership. If you dont like the 2012, just refund your reservation. Whats important is to get the ball rolling for the financing process. You need to cOmplete all requirements before the dealsership will pass all your docs to the bank for evaluation and credit investigation process.

I cant say what papers do the dealership will ask from you since most of the time i use my bank in getting a new unit. Different requirements for different people/status/occupation. Kaya its best to visit a dealership first to know all this stuffs.