My understanding is that it's not a problem so long as there is actually a functioning cat on the car, as opposed to just a "test pipe" or a blank, but I could be wrong. Hate to sound dorky, buy you may want to check with your local authorities.
call o.d.o.t. and see what they have to say. try this number, it was listed as odot customer service 1-888-275-6368. if that's not the right one they should be able to give it to you.
my guess is they might want you to smog test it after install and see if it still passes.
"Under Federal EPA regulation, replacement of original catalytic converters is allowed only if the original converter(s) is missing, or the vehicle has more than 50,000 miles or is at least five years old and the need for a replacement has been established and documented, or a local inspection program has determined the existing converter is in need of replacement."
And there's that lovely bill going through our fantastic legislature right now giving CARB even more power. Like the power to implement new taxes, like +$.50 per gallon of gas, +$.02 per mile you drive, and a couple more I can't think of at the moment. Yay CARB!:barf:
It might depend on your state too. In Ohio the have the useless E-check emmisions testing. The only thing they do to check the cat is look under the car. They don't even bend over to look, they just take a mirror and look for it. I am planning on taking the cat out and putting a straight pipe on it. Then taking an old cat, cut the top from the bottom and strap it to the new pipe for e-check purposes. Then if it passes good, if not I will go home put the cat back on and go to another testing facility. If you don't pass they just tell you to get it fixed and come back. Plus you only have to get it done every two years. I also want to get it dyno'ed bofore and after the cat is removed.
In Mass its even worse. They actually put the car on a rolling dyno and check the emissions at 2500 rpms. I have yet to see them do it with an AWD car although I'm sure they have a way to do it. I've see people get cars rejected because thier gas cap didn't pass a pressure check. It's all computerized and goes directly to the RMV so its though to get around. You also have to go to the same place that failed you the first time to get inspected again AND you're supposed to get you car repaired at and authorized RMV repair station the is certified to repair cars that were failed during inspection. What a freaking scam.