It's funny you say that, since last year the EPA went down a who's-who of those that make exhaust components and sell exhaust components in the US. One of the first, most basic things, that you do is to replace the exhaust to open up flow and improve performance when you're building a race car (and reduce weight). Additionally you do tuning of the engine management system, which the largest provider of was a company called EcuTek that also had an enforcement action. https://www.epa.gov/enforcement/national-enforcement-and-com...

I mean... if you're building a race car, which is offroad use, and legally allows you to defeat emissions devices, but the EPA has taken enforcement actions against everyone who makes them or sells them, where are you supposed to buy them? I can do my own exhaust work, but I can't sit down and build my own ECU programmer that bypasses the encryption that the manufacturer puts into their product and debugs their proprietary CANbus protocol to reconfigure the fuel system mappings. I mean, I probably /could/, but we're talking about years of dedicated work on my part, and I'm sharper than the average racer when it comes to technical things. Typically you get at most 4-5 months to prep a race car for the following season.

The PR twit at the EPA can say whatever they want, but the proof is in the pudding and actions speak louder than words. The EPA fucked over everyone who does amateur motorsports in this country, point-blank.