Just so you know, I don't know what year your car is and if it is an Aveo, but the part numbers I have been giving you have been for a 2005 Chevrolet Aveo Hatchback LS. The hatchback LS doesn't really matter when getting parts for the exhaust I don't believe. Most of that parts though are interchangeable for Aveos 2004-2006 I believe but I would search parts for your specific year and everything to make sure you get exactly what you need.

Being that it is OEM I believe it would pass in California. If you call the (877)582-0162 number from the HPExhaust website while they're open they should be able to set you up with a cat if that one isn't approved for California. If nothing else go to

MagnaFlow Catalytic Converters - CALIFORNIA STATE Catalytic Converters For Trucks, Suv's, American Muscle, Diesel, & Sport Compact Vehicles

Enter in your car info and then click on the direct fit number and then click buy online, and then look through the list of banners and click on em to compare prices and shipping rates. Some say that they are free FedEx shipping and others charge. You will just have to find the one that suits you best. But I am pretty sure that all of them ship to anywhere in the USA.