My prior class c (a Forest River) came equipped with the Firestone Ride-Rite system which worked great.
The system can be self installed but you have to be careful before ordering. Not sure about the Class C's but Firestone claims that on the F53 chassis Class A's Thor places body mounting brackets in the location where the Ride Rite mounting brackets should be placed. A few of us have looked and there does not appear to be an issue with body mounting brackets as described by Firestone.
US Army (Ret)
2020 Entegra Accolade 37TS
2019 Jeep Grand Cherokee Trailhawk (Toad)
FMCA - F432054