I've spent about an hour searching through the forum posts here and have not found anything regarding Aftermarket catalytic converters for a 2006 V6 Touareg in California. My cats need to be replaced and the approx. $3,000 cost is unfortunately prohibitive for me right now. I was told by a smog tech, a muffler mechanic, and a Non-dealer import repair tech that they can not install the much cheaper aftermarket cats that are available for all the other states to install on their 2006 V6. What I want to know is how would the smog technician know that I have aftermarket cats? Are they wired into the car's computer and reveal their origin when the smog tech connects their computer to the car computer? I have seen aftermarket cats available on eBay for my 2006 V6 and have confirmed that the seller will ship to me. Since they are 'bolt-on' kits, I could just do them myself as long as I know that the smog inspector would not be able to tell that I'm running aftermarket cats. I've also seen used cats for sale at local pick-a-part type yards. I read somewhere on the internet that California won't allow used cats to be installed as replacements on my car. I'm hoping someone here can help clear up all this cat BS for me. Thanks in advance for any help you might be able to offer. Feel free to PM me if that makes you more comfortable.