Well, usually, every vehicle that is manufactured has a catalytic converter equipped and you will need to maintain it over the years. However, when you decide to buy catalytic converter you are probably uncertain whether you need a metallic or ceramic catalytic converter. The thing is that nearly all vehicle come with a ceramic cat, but if you want to increase the performance of your vehicle you could buy third-party aftermarket cat that has a metal core.
Every catalytic converter measures the flow of exhaust gas with CPSI which stands for cells per square inch. The more you have the better exhaust system you own. A lot of manufacturers true to offer you good CPSI and at the same time increase the power of your vehicle. When you are buying one, be sure to speak with your retailer and see if the CPSI ratio is good for you and the amount of power you get.
If you are into sports cars and racing then you may pick 100 cell metal cat, while if you have a normal commercial vehicle you will need to pick a specific euro rated cat. Nearly all new cars come with euro 6, so you do not have to worry about having a problem with the law.
Whether you are buying a cat for racing or you want to better your older car, there are dozens of retailers who can offer you a wide range of cats that come in different shapes and sizes. Generally, cats have a universal fit, so you do not have the extra problem, however, to be 100% sure that the clearance under you car and space will fit the cat and you can always ask the retailer to check if the cat will match your car. Another special feature that few retailers offer is the "bolt-on" options, but to get it you will need to acquire additional pipework and flanges to have a perfect fit for your vehicle.
In the end, you know have the right information before you go out and buy catalytic converter and be assured that you have made the right decision for your vehicle and for the environment.