When your cat needs replacing it is worth considering upgrading to a Sports cat. Particularly if you drive a performance or modified car.
A standard ceramic or metallic catalytic converter uses a monolith (the internals of the cat), that has a density of approximately 400 cells per square inch (cpsi), while Sports cats utilise a monolith with a density of 200 cpsi. The lower density of the 200 cpsi monolith means that the cat has the ability to flow the exhaust gases at a much increased rate and therefore liberate extra power.
To make the use of the lower density possible, and still pass emission regulations, the monolith must contain higher levels of precious metals (usually platinum).
The difference in cost between the standard and Sports cats is largely due to the extra precious metal content.
