I can't tell you what to do, but I'll tell you what I'm going to do. My passenger side rear was junk, and both fronts were "decent", and the drivers rear was good. Well I bought the passenger rear, and started cutting, and cutting, and cutting, and then I decided that I was going to really check how good the front was going to be, and decided they needed replaced too... Well the floor support needed replaced too, so I decided the best thing was to be by the time I replace the three sections, just replace the whole thing... So out came the whole floor. Now mine is gutted, the engine was just sitting in there not bolted down, even to the engine, so it was no question on that either. In my opinion, you need to either get the whole floor, or both half sections. I think if you get both half sections, you can replace them without pulling the engine/transmission, but I think you'll be glad you did for when you have to clean up the front lip. Also, the two half sections will be easier to handle by yourself if you can't get any help.