I checked the car (X11) out as for balance.
As you can see, it's pretty good in balance:
I also measured the weight:
780-isch grams on the rear side and 680-isch on the front-side, which seemed pretty good for me.
But eventually I added some weight on the middle of the car, around 60 grams, and then some weight under the front shocks: 40 grams.
So the car is now around 1600grams in total