Here is my recent fun with this topic. Keep in mind that I'm in El Paso County with no emission testing (for now). Last month, I took my 82 Pickup for a new exhaust system, including a new cat, to my favorite exhaust shop in C/S. He filled me in on the CARB certified cat required and the massive expensive of the parts. He said if he installed anything that was non-CARB certified and it was not on his approved "list" for an 82 Pickup, he would be facing something like a $45k fine. He was very frustrated and then went on a 15 minute rant about where this state is heading. He built his business specializing in custom exhaust for classic rigs like we have and knew these new rules would have a big impact on his business.
Fast forward to what I ended up doing. As you may know, you can't buy a non-CARB certified cat on-line, because they will not ship it to CO. I refused to spend $600 for a CARB cat so I bought a 48 state approved cat through my sister who lives in Kansas. She shipped it to me and I had my friend install the exhaust system.
I love this state but if we are becoming the new CA and I can no longer drive my junk around town, then I'll be going elsewhere.