Several cars that have them (I read this in the group buy) in SO. Cal pass thee tough e-crap with flying colors, thye just let the car run for a bit to get the 3rd cat warn enough for it to do its job. I have to get my car e-crapped this year and will have headers on it by the time it needs to be checked.
There was a group buy on the MSDS headers from CTA Motorsports, check em out at
http://ctamotorsports.cjb.net or email Chirs Wong (he's also a CEG member) at chris@ctamotorsports.cjb.net the bad thing is there is a month wait atleast. I will have mine by June when I paid for them the second week of April. The headers are like $550 plus shipping, I got the Vortech Spec ones for the SC later, looks like I'll be putting them on at the same time now.
I cant say for sure if it will pass, but its a risk I am willing to take.