Best Emissions Legal Catted Header & Exhaust?

[Ammunition]

Originally Posted by CruiseZen

Well, so far this thread has been viewed 279 times and it appears that not one of those people has swapped headers and passed a state mandated exhaust emissions inspection. I want to make one more attempt to see if anyone has actually done it before this thread sinks off the front page.

I am curious about this as well as I m interested in getting a header, but my FR-S is the first car that I've owned, so I have no experience ever taking a car in for inspection. Given the number of horrific smelling pick-up trucks, and older vehicles I see (and smell) all the time around here, I can't imagine a newer car like ours should get a hard time with it, even if the header is catless, so long as there is a cat somewhere in the exhaust system, but like I said I have no experience with this, so it's something I'm worried about as well, and which I can't seem to find a lot of information on.

All I know is that my county is one of only two in the state that require an emissions test by the DEQ, and I've heard mixed stories about people passing it without issue with heavily modified exhausts, or getting a hard time for it, so I'm not sure what to expect.

[Infamous Performance]

Technically, because the cats reside in the header section (are considered to be part of the header) no header is legal in any US state. It is a violation of DOT regulation to remove, modify or alter a catalytic converter in known good operating condition on a car 10 years old or newer.

[akyp]

That's why I'm keeping the OEM frontpipe. I swapped to P&L catted header and already notice more smell during cold start. I wonder if a good tune would help passing a sniff test but I won't need to worry about that in 3 years.

[churchx]

Not sure if cold start should be thought much as benchmark descriptive enough for exhaust content at normal running. It especially plays with cam and ignition timings to throw more unburnt fuel so to heat up cat sooner. Hence the noise, hence the smell. But will it be as bad on warmed up engine exhaust? I doubt smog checks will first require hour+ for complete cooldown of vehicle, no?