An integral part of increasing the speed, agility and overall performance of your RC Car is to reduce its weight. There is a host of options out there, from lighter tyres to
aluminium and carbon parts. Of course this is going to be largely budget dependant in terms of how far you go with this, but believe me, even a marginal weight saving can have a drastic impact on your rig performance!
However, remember that an RC car still has to follow the same nfewtonian laws of
physics, with a lighter rig comes lesser traction, so this is something to carefully consider and balance your considerations like other factors to do with your driving style, especially if you love going heavy into the corners. All part of the fun!