Good information, Jon, and an excellent business decision as well. One cannot risk his livelihood to put a big target on his back, even if he has the knowledge to make those modifications. The Clean Air Act of 1968 that brought about a lot of the smog regulations provides for a $5,000.00 fine and/or 5 years' jail time for EACH example of making an emission-regulated vehicle (or part) non-compliant. Back in the mid-1980's a muffler shop in Nashville was caught with 4 vehicles ready for delivery to the customer with "catalytic converter test pipes" installed. The "customers" were federal agents. The shop owner paid $20,000.00 in fines and went out of business shortly afterwards. I fought that battle in California in the 1970's, and their regulations exceed the requirements for America. I was "encouraged" to make illegal modifications by drive-in customers I didn't know, and their requests just didn't pass the sniff test. "Nope- - - -try some other shop!" I was running a dirt track race car at the time, and some of the more radical proposals that didn't make it into their regulations were to make emissions standards apply to off-road vehicles, including race cars. We did have to run mufflers at some of the tracks, but that was the result of local noise laws, not statewide requirements!
Jerry