Boot, there are only 2 companies that make the inside bricks for US cat converters in the world. My converter manufacturer just did a 5 hour presentation for my guys on Friday. All bricks are the same,hi flow, regular flow, whatever. The "high flow" cats are the same bricks put into a larger body, thats it. Pay more money but nothing changes internally. I sold 12000 Flowmasters last year and 36000 new converters. We recommend applications to customers hour after hour , day after day. I sponsor 3 drag cars, national points winners, and nobody runs cats. Look for them in Gainesville in 4 weeks. Trucks with big trailers in tow up hills with stock exhaust can easily get a converter glowing, thats what they do. Let the guy buy what he wants. I was designing cats and fuel management systems in the early 80s and the technology hasn't changed one bit. Peace.