It might depend on the state, In TX where I live an emission test on the VX consists of pluging in to the OBD II port and checking the exaust there. I have true duals as well, I am going to go back and put an H pipe as well. I love them, I have flowmasters on it right now, and they may be to loud for some but I love it! Oh by the way Apostle you may want to check with your local emissions inspection station. I used to live in denver, and make trips there frequently, about 3-4 times per year. I have been pulled over by colorado PD at least 4 times telling me that it is illegal to modify your stock exhaust system. I don't know if it is true because they never gave me a ticket, just a warning, so I thought you might want to know.