Hi, have a friend with a shitton of miles on his 328i.
His check engine light is on, the cats and O2s are bad. Gonna cost an assload to replace the parts with OEM spec shit, was wondering if there was some aftermarket exhaust that isn’t loud but sounds good and replaces the cats (must be street legal) that is a little cheaper.
like i said, if the exhaust itself is in good shape, and just the 2nd o2 is bad or the cat isnt up to snuff, then a $40.00 O2 simulator from ebay willmake that pesky light go away after a reset.