I think I agree with Loren on this one. Get to know your car in race situations first. Learn what it does in corners, learn how to correct understeer or oversteer, etc. Then you can start modding it, or losing weight. That way when you take it out next race, you can decide if you like the way it responds.

Giving an analogy from my world, you don't start out right away going sideways on the gravel, you gotta learn how to brake smoothly, set the car up for the corners, etc first.

Gotta walk before you can run!