I have a CEL with P0134 code on my M5 2009 GT with 124K+ miles. Most likely O2 sensor needs to be replaced for the first time. I just wanted to hear about experiences/opinions of those who have replaced theirs. Did it clear the code? Dis replacement last? Did you use OEM or aftermarket (denso or ntk or other brand)? Also, does anyone know what company makes the OEM sensors for mazdas, particularly mazda 5s? Thanks.