Been reading the SRW vs DRW threads... I have never towed with a DRW and I'm curious what everyone means by "stability". Can you describe what you're experiencing that feels more stable. To say ...
Its simple physics. With everything else being equal (and its not, DRW generally have slightly different components to handle the increased payload capability than SRW) the DRW has a wider stance making it more stable in any side to side action. If you don't believe it, test drive one and listen to the seat of your pants.
(old farm boy here, I can tell without any doubt pulling livestock trailers with 1 ton SRW versus 1 ton DWR there is a definite difference)