Your own LIFE, as well as LIFE of other passengers and other participants at a traffic, depends directly on BRAKING and STEERING system. If you are not a qualified mechanic, DO NOT DO ANYTHING about these systems!!!!

SUSPENSION system has no less influence to the SAFETY, and requires some special tools - so it is another system whose maintenance should be left to an expert.

Some complex jobs about  engine, clutch and gearbox also require special tools and high skill level. You should know how far you can go, otherwise you can have more problems than solutions.

Carburetor can be pretty simple thing when you know the things, but keep in mind that the improper carburetor adjustment can cause serious damages of some vital engine parts (pistons, rings, heads, valves,...enough?) or at least low performance followed with increased fuel consumption. Another thing, there are some elements which were adjusted in the factory with high preciseness, whose position must not be touched. Anyway, you should not be afraid of the carburetor jobs, but consult some experts or literature before doing anything since it requires certain level of knowledge and experience.

If you customize or repair electrical system, be very careful because some mistakes can cause a fire (!!) , or at least discharging battery during the time when the car is parked, and this is unpleasant enough (I know from my own experience).