Mason,
I see what you are trying to do by keeping it "real". And yes driving and track time mater the most. But from my experience, some of the steering comes from less weight, but not super light. For instance, the light weight tranny stuff take about 50 grams out of the diff, which should free up the rear. I run my car at about 1550-1560 with the body on. I didnt go crazy on the weight, but I did do the tranny stuff. The light weight tranny stuff seemed to free up the rear, lower motor temps and the car spools up power better in 17.5. If you are running mod, then yeah you dont need all that. I think rivkin runs just over 1600 in mod, so about where you are.