If you burn metal rods into the plastic r/c parts will that reinforce and strengthen the plastic or make it weaker around the metal????

i doubt it.

Jeepers, If you get the metal to hot , you will destroy the plastic. It also depends on the plastic. Thermal set or Thermal cure . Thermal set means as it cools it sets , can be remelted. Thermal cure means its a done deal , reheat will just destroy the material.

Andy