THERE IS NO SUCH THING AS A HIGH FLOW OR PERFORMANCE CATALYTIC CONVERTER!! A catalytic converter has no moving parts nor is chambered like a muffler, or have elaborate packing like a muffler. Well this may come as a surprise to some and will really bust the bubble of what some companies are selling. We get calls almost everyday from customers wanting to know how much a 'high flow' or 'performance' catalytic converter will cost for their car. There are many companies on the web today selling what they call a 'high flow' or 'performance' catalytic converter.