wheelnut a lighter car is faster in top speed but not always around the track, a heavier car is more stable and less likely to crash + has more traction. so its easier for him to make less mistakes during a race. Fact is you could take all the fastest guys in the world and put them behind the wheel of a rustler and they would still smoke 90% of us.
Hooray for the underdog thats what i say if every track had a racer like you racing would be much more popular.