2003 BMW 325i
Unfortunately the day has come when my cats have gone bad. From the looking that I've done, it's quite expensive to get these replaced. I was thinking a potentially cheaper solution would be to replace the headers with the Active Autowerke headers, as well as some after market catalytic converters. One potential issue I see with this is the O2 sensors, and possibly some engine codes. I'm not sure if this has been done before, but has anyone done this? If so, any tips? Would also love if y'all could point out other potential issues with this fix, or other fixes you've done yourself. (I would like for my car to still pass emissions is what I'm aiming for).