800 series will be much more stable with the duals. Also, you can use low range transfer in any gear you wish. I can't believe the army would accept a truck like the 900 series for a tactical truck that along with its lack of redundancy due to the complexity of electrical systems also has limitations in low range transfer case. We use low range, need it in many situations we get into with our trucks, especially the dump. We have the M series, do not expect high road speed, a sacrifice so to say for the uniqueness of the military trucks and the attention they get. Many contractors have told me they want to find a military dump like the M or 800 series but have a hard time doing it. Go for it! If you can afford it while keeping your 900, go for it! If not, you are still ahead to sell the 900 and go with the 800 series dump. If you have mechanical ability, the 800 will be much easier to maintain with common mechanical knowledge without having to try to sort out complex electrical systems, tire inflation systems and such when things go south on the 900. If I remember right the 20,000 pound winches are not as expensive or about the same as the 10,000 on the deuces because of popularity difference. Also, the shaft drive 20,000 pound winches are honest 20,000 pound winches. The hydraulic winches on the 900 series are the same basic winch but the capacity is lower. I was looking at a 900 series wrecker a friend has and could not believe how much lower the stated capacity of the front and drag winches was compared to the M series shaft drive winches we have.