It seems the other factor not being taken into account is what type of track one is running on. My home track is carpet and very grippy. Depending on that tires you use, a light car will either work well or traction roll at every turn.
One of our consistently fastest drivers is a big advocate of adding weight. His car handles like a dream and is somewhere around 1500 gr. The basic theory is to make the car stick to the track no matter what. Seems to work well for him for his combination of tires and springs.
Others are running minimal weight and super sticky tires and finish well.
The most important thing we've discovered is that the car doesn't have nearly as much to do with winning as the driver does. All of this super-fine tuning is complete overkill, and frankly those carbon shafts don't do a damned thing for you. A few grams located a few mm above roll center really don't matter that much.
Jim