agile is the only place that has custom valving for these heavier vans, with a few options depending on actual weight of your specific rig. kinda silly to purchase anywhere that doesn't offer that option when its available. keep in mind that john worked for fox for quite a few years before he worked at agile. he knows fox shocks inside and out. no brainer imho.
"understeer is when you hit the wall with the front of your car, oversteer is when you hit the wall with the rear of your car, horsepower is how hard your car hits the wall, and torque is how far your car moves the wall."