Just to clarify, there is no such thing as "49 state legal." That's a made up term that basically means it will not meet CA emissions. Since CARB was established BEFORE the formation of the EPA, CARB was granted allowance to govern the state of CA independently. This works because CARB standards have consistently been more aggressive than EPA standards which govern "the other 49 states." CA is the only state with separate emissions and air standards. As for the other responses in this thread, they are correct that unless there is a CARB "E.O" number clearly and visibly stamped on any aftermarket part touching any component between the air intake and the exhaust tip, SMOG can fail you - though the inspectors really only look at major intake components and exhaust items through the exit if the catalytic converter.
Here's the real clinker, and it's going to be a huge headache moving forward. EPA standards apply to ALL 50 STATES, and explicitly prohibit the tampering of ANY factory emissions system on any vehicle manufactured during or after 1975. Doing so is a direct violation of the Clean Air Act and is a criminally punishable offense. Only some states have smog inspection, so the assumption by many has been "if they ain't looking, I ain't breaking any laws." Not to be a doomsday'er, but with the current administration overseeing the White House, the Senate and Congress, and their stated objectives to significantly advance global clean air initiatives, don't be surprised if you see 50 state emission inspection become a thing - very soon. And, every car manufactured after 1975 that doesn't have factory emissions will have to either cease operation or have to be returned to factory emissions compliance.
Sounds like a horror story, right? Noodle on this... How do aggressively force a transition of transportation infrastructure to EV? Well, one simple way would be to start enforcing existing EPA laws in "the 49 states" outside of CA. Additionally, if you subscribe to the belief that increasing taxes is a sound economic theory to generate revenue, consider that requiring all 50 states to start SMOG inspection would generate Billions in service fees, equipment investment, tech training, state and local fines, etc., not to mention leveraging many consumers to buy EV.
Just to add some more salt to the wound, if you think laws can only be made by the legislator, you'd be wrong. The EPA is the ONLY exception to that rule. The EPA, as a government agency, has the privilege of creating law with absolutely zero debate from either political parties or lobbyist.
Maybe this is all just me wearing my tin foil hat, but that's the writing on the wall I see...
