Make sure your floor is thick enough for a two post. And good strong concrete. My floor is 8 inches thick. I saw one rip out of the floor when the guy was jerking bolts loose. Destroyed the car and the garage when it went through the wall. 4 post are safer if you are not sure of the concrete you have. Or cut the floor and pour columns in the ground.
A lift is only as safe as the installer or operator. BE SAFE !!!