I'm not gonna give you any details about the last mission (no spoilers here). The only thing I can tell you is after a mission you will get a new pink slip car (which will be a BMW). Then the last mission begins with you driving this BMW. It's not the best car for this mission - in fact the car is not good at all especially if you were driving a Pagani Zonda fully upgrade (like I was before). The good thing is: you CAN change your car before the mission. Choose a good, fast car with nitrous (Tier 1 fully upgrade recommended)!