NHRed: I looked and looked and finally found one person who had bought and installed a Vortex muffler. He hated it. It droned and his gas mileage actually went down. He said he had to change it, got an Aero muffler and is now delighted with it. The sound is great, he gets lots of compliments on it, his mileage has improved 15% and he couldn't be happier. I searched and searched and couldn't find anyone else who had even heard of Vortex. I'd list his name and phone number but he doesn't want to be bothered. He is out driving his car with the new Aero muffler on it. Walk