I assume that the Class C does not have the capacity to tow your race car trailer. If the issue is hitch strength, there is a population of racers who have upgraded their hitch to tow heavier trailers. If the issue is performance, that is more challenging and likely one you should avoid since you have a solution working.
So, if the C is not good enough for you, it likely will fall short for other racers. Maybe a lighter weight class racer could use it. In all likelihood it's going to be hard to find a trade. Suggest you sell the C yourself. RVs seem to be popular now. Worth the effort. You can always fall back and trade it for something that works for you if it does not sell. Good luck with your effort.
Travel Safe and with a Smile! Pat