Headers Vs Emission testing

[rcd001]

Been looking at a full header back exhaust and I'm a little worried. Most seem to replace the "primary" cat. I'm concerned that if I make this change my car will not pass the emission tests plus it will hurt mother nature a whole lot more.

The M3 has 2 cats, correct?

Is their a header out there that will let you keep the primary cat?

Also I understand that if you fail the emission test you need to spend up to $250 on upgrades and then you will get a conditional pass for the next 3 years. Could someone do this mod and then just buy a new high flow cat every 3 years ($300 - 400) installed?

Sorry if this seems foolish and I have searched for this but I am still confused.

Thanks team

[Wild Weasel]

I replaced the entire exhaust on my Sunfire, including the cat and a header. When I was doing it, the shop gave me two options for high flow Magnaflow cats and said that one would pass and the other might not. I took the one they said would pass.

They were right. Passed with flying colours.