Our GMC is a SRW and we are under the weight specs in all areas, not by much, but under. Maybe our experience is different but ours is a very stable, very comfortable, easy to stop ride. We have put 16K miles on it in the past 2 seasons and hit some very stiff crosswinds, especially on I70 in western Kansas and eastern Colorado and never once felt unstable or even remotely unsafe. We do have a set of Air Lift bags on the truck and 7K axles with disc brakes and J rated Michelins on the trailer. I have a Trailair Center Point air suspension system sitting in my shop waiting for the weather to warm to install on the coach. We hit some really rough roads in our travels last year and am hopeful this will help calm the earthquake inside the trailer.
My truck is my daily driver and it is not much different than driving the half ton I used to own.