Radio Controlled Model Cars are very fragile and easily broken. The main parts to protect are the Front A-Arms, Wishbones, Suspension Shock Towers, Shock Absorbers (Dampers), Hub Carriers, Kingpins, Uprights and Toe in Blocks, so make sure you have a good strong Bumper and Lexan or Fiberglas Body Shell, with, if available, an under guard/tray/panel and Roll Cage. For added protection you can line the shell with the waxy type of polystyrene you get in many electrical goods boxes. This can be easily shaped with a modelling knife to suit the curves of your shell and held in position using Shoe Gum. (Also recommended for fixing splits and rips in your Body Shell)
The Steering Servo is also a weakness in High Speed Side Swipe crash situations, so get yourself some good strong Servo Mounts/Stays and Servo Saver. Also I would recommend Titanium Shafts, Turnbuckles, Tie Rods and pivot/steering shafts and if available for your model, lightweight Titanium Drive shafts, dog bones and CVD (Constant Velocity Drives). The standard steel types are far too easily bent.
Gearing is another area of weakness on model cars. Head on collisions can easily break off gear teeth on Nylon/Plastic Spur Gears and even Bevel Gears inside the Gearbox (Gear case/housing) heavy impacts can also loosen nuts and or self tapping screws that hold the Motor in Position, allowing the Pinion Gear to pull out of mesh slightly and rip the tops of the teeth on your Spur Gear. To avoid this to some degree, fit Nyloc nuts, and a new motor mount from time to time so the self tapping screws that hold the motor in position have less chance to come loose.
Many New car kits come with Nylon and Sintered Brass Bushings. My advice is to bin these before fitting and buy a good Hop up set of Shielded Ball Bearings. Or if you are serious about your racing, Teflon Ceramic Ball/Roller Thrust Bearings.
One final bit of advice about the Setup of your Car. Keep the Centre of Gravity as low as possible. Ride Height is all important. For On Road Drift/Touring cars the Ride Height should be no more than 5mm, for Buggys, Trucks, Truggys and Monster Trucks, as low as possible depending on the track conditions. If Body Roll is a problem, handling can be improved with the use of Stabilizers, Anti roll or Sway Bars, stiffer Tuning Springs and, or thicker Silicone Oil in the Dampers. Also find somewhere to mount the Transponder as low in the Chassis as possible.
For Car Setup Information check out our Hints and Tips page.