1. The minimum volume of the mufflers has to be a minimum of five times the engine capacity. Therefore, if you have a 1.0-liter engine, the mufflers have to total a minimum of 5.0-liters in overall capacity.

2. The diameter of the pipes should be about 30-50% larger than the stock ones. The larger pipes will allow your engine to breather better thereby resulting in cleaner combustion

3. Always remember to add as much glass wool stuffing as possible into the muffler bodies before final welding and sealing them. This rule though, is only applicable if you are custom fabricating your own exhaust.

4. Avoid large exhaust tips. Not only do they look out of place on smaller cars but are also a magnet for the police who are out to make a quick buck.

5. Always use the best quality of steel pipes, preferably seamless for the best quality fluid flow in the exhaust system.

6. One can also use stainless steel pipes if the car in question is not run regularly. That said, a stainless steel exhaust is more durable and ensures better performance as the metal reacts less to the exhaust gasses. Stainless steel welding though, is more difficult.

Always remember, every single bend in the exhaust system has to be flowing and smooth. Sudden bends of any sort will not only disrupt the flow but the extra back pressure may actually end up ruining your engine.