I prefer tire balancing weights, too. Got them for free and because of their size 5 or 10 gr. you can place them everywhere in the car. Would prefer running without them but rules say 1400gr. and the allowed electronics are that light, that my 5400 50C battery has to much weight on its side. So I carry always around 100gr. extra weight in my car...
By the way only HB bodies are allowed. Mazda works fine, but looks boring. Today I tried to convert it into a BMW 320 TC in the WTCC Tom Coronel style:
This is the real one:
