The only reason I like lower weights is that I’m getting lazy in my old age. Plus, my back don’t like it much either. We normally run at 365# and we usually have 35# on the kart. When I saw this talk about 375 or 400, I thought, holy cow. We could have seat failure from all the lead attached to it.
In an endurance race, its all about keeping it on the track. The lighter weight could have an advantage on tires, and drive line wear. But then again, a driver who slides the kart around will ruin tires regardless of weight.
In a straight up sprint race, the weight would be a huge factor, we all know that. In an endurance race, we certainly won’t be running at max all the time. Rather, we will pick a lap time that is quick, but not excessive and try to hold it. Good preparation of the kart and drivers who are gently on it will win.