A pretty standard performance sway bar kit tubular front and rear non adjustable bars.
Front vs rear sway bar.
Likewise a rear wheel drive car with an overly stiff front sway bar may tend to understeer.
The rear bar you d need for your 2014 motorhome on a e450 chassis with a factory sway bar is the part rm 1139 147 and then for the front rm 1139 176.
I had a 28mm rear sway bar on my 01 jetta and removed the front sway bar which according to shine racing at that time was the way to go.
I ve been told the rear sway bar links actually limit the droop travel on the rear.
Personally with the upper and lower strut bars added to the car i really liked the set up i was using koni adjustable struts set hard on the front and med.
Changing the settings from hard to soft made it over steer but set right i could take the.
While increasing the stiffness of the rear sway bar in a front wheel drive car might reduce understeer an overly stiff rear sway bar can actually induce oversteer and make the car difficult to drive.
Front sway bars stabilize the front tires while back sway bars work to provide more rigidity to the rear tires.
Stiffer sway bars are not always better.