Why risk getting an unknown quality LSU4.9 when you can get the genuine Bosch Motorsport oxygen sensor from us. Sensors that come from unofficial Bosch sources can actually be defective units that did not pass Bosch's strict end-of-line quality tests.  Accurate measurement of lambda (air/fuel ratio) is critical to engine performance and longevity, so do you really want to trust your engine to be protected by something that quite literally may have come out of the trash bin??   Price is per sensor.