I don't think that matters as much as you might think. We have 3 race classes at our local track. The Pro guys (top level) are easily 1-2 seconds above the Pro-am guys (mid-level). Some of these pros are not exactly lightweights and are considerably above the minimum weight. Yet they manage to slaughter everybody else out there. You would think they had a disadvantage to the people who are running the baseline weight in the kart, but you sure can't tell it.