It depends on what you call more stable. By take and pushing sideways on my dually and pushing sideways on my SRW they both had the same movement. My dually has a bigger sway bar and weighs more and has a longer wheel base than my SRW so naturally it's going to take more to make it move and roll side to side but the extra two tires makes no difference from a side to side movement. All 4 sidewalls on my dually flex just as much as the sidewalls on my SRW from side to side. Yes I have pulled my current fifth wheel with both a 2005 2500 and a 2010 3500 DRW. Both were quad cab diesels with the same exact tires (size, brand and model). The only difference was sway bar, long bed on the dually and springs. I sold the dually because I still prefer to tow with the 2500. It handles (between my two truck I mentioned) better, easier to get around in and has no stability issues what's so ever. The wind and passing trucks have no more effect on my 2500 as they did on my 3500 DRW. This is just my take on the two I have/had.