In the mission, "Lure" for Wozzie, you will have to lure the Viatnamese out into the countryside. When doing this, you have to take a Rancher SUV. During the mission, the SUV will be dent-proof, meaning that it won't get dented by anything. To keep it, just go to one of your safe houses with a garage and store it there,and boom, you'll have a dent-proof Rancher. If you decide to finish the mission, keep the Rancher and shoot it. You will notice that it is invincible to bullets or even the rocket launcher!! So, store it in your garage, and you will have a bulletproof Rancher.