The only weight i run in my car is the Ghea 35g brass bulkhead...
I find the car suits me this way.
BUT... if you have big jumps like we did at the Talywain National i tried 60g of lead under the lipo (approx half the size of where the battery sits..) in my final.. adjusted my ride height and found the car flew much better.. rather than having to think about the approach and my speed i felt i could just " drive " the jump..
im going to experiment with more on " jumpy " tracks!
It didnt really seem to upset the car anywhere else on the track.. the only thing was it maybe didnt change direction quite as quick..
Cheers
Nick