I installed the Sumo Springs on my 2018 Thor Siesta 24SS which is built on a 2017 Mercedes Benz Sprinter 3500 chassis. They are easy to install as long as you are able to raise each wheel (one at a time) to gain additional space to remove the old factory bump stops. They make a huge difference in the side to side swaying motion going into/out of driveways and on the road when being passed or passing large trucks.
My 2012 MB. Came with sumo springs installed on the rear by the previous owned. I can say it doesn't sways much at all. I've read posts that people who install them on the front remove them as they harden the ride. My toad is a 2001 Jeep TJ. Just over 3000 lbs. There are many around so finding a good one under $10 k is not to difficult.
I just sent you a private message. I am on my 2nd MB Sprinter chassis motor home. My 1st was a 2016 Winnebago ERA Class B that I bought in Aug 2015 and my current one is a 2018 Thor Siesta 24SS with the summit package that I bought in March 2018. Love it. Handles great, good power and fuel economy. The 2 slide outs make it roomy when parked.