Replacing both can set you back as much as nearly $700. For one front sensor, it is around $300 to $400, a good deal of which is labor. The 2008 328i has four O2 sensors - two in the front and two in the back. They work in conjunction with the OEM Mid-Pipe and are easy to install using clamps instead of heavy flanges to reduce weight in the exhaust system and provide proper alignment and positioning of the exhaust.
2008 bmw x5 4.8i, xdrive48i, xdrive50i / l6 Megan Racing Axle Back Exhaust are designed as a direct bolt-on to replace the stock unit.
