Cheapest way to make it sound better would be the catback and suitable muffler. Definitely avoid the cannon and you don't need to replace your cat. It should only cost you at absolute most $250. How much would a full exhaust set up cost roughly? Depends where you go. Most places I went to to get headers done just said no; too difficult. You can buy from the US headers for the 1mz-fe but by the time they are shipped and customs is paid; you are better off buying local. For reference my setup is (with their approximate cost): - Equal length, mandrel bent headers, Mild Steel - $2200 ($2600 for ceramic, $3200 for stainless) - 2.25" Catback (reusing the cat) with Lukey Turbo Muffler + stainless tip - $400 I was incredibly impressed with the exhaust note, power output and increase in fuel economy. I gained ~9-10kW at the wheels and my fuel consumption dropped from 14.5-15.0L/100km to 12.7-13.5L/100km. Catback price was expensive but it was easier to get it done at the one place. CES did my headers, I don't know if they still have the template for the headers but if they do the cost will probably be much cheaper. If you do get them done, pay the extra for the ceramic coat. I wish I did.