Walker is your one-stop exhaust shop, offering a full line of mufflers, pipes, hardware and accessories. Cat to Y pipe intersection showing after cat O2 sensor location. This qualifies as one of the STRANGEST stock exhaust parts I have seen. For some reason Toyota/Lexus decided to weld a straight section of 60mm pipe to the cat outlet flange, angle cut it, weld a 50mm pipe pipe that has its last couple of inches expanded to 60mm and match angle cut. Also note the O2 placement is in the 50mm sections of the Y pipe where the sensor tip takes up a good portion of the available flow area.

The difference in fuel economy is, however, more obvious while driving on a freeway. They also do not offer the best performance due to many reasons. If you're looking for an off-road exhaust with&nbsp