Doug Thorley Y-pipe. Fits 2007-14 FJ/4runner 4.0 V6. Exhaust tone is slightly more aggressive, mainly the piping is smoother and flows better than stock. Replaces rear cats for resonators. Off-road use recommended. I'm a believer that my average mpg increased about 1.5mpg cruising after logging mpg data. Heat wrapped, gaskets and hardware included. $300 shipped.