These pipes are really well made. The welds are exceptional and they are thick! Unfortunately, they only have an O2 sensor bung on only one of the mid pipes, not both. This bung is not even intended to be used for an O2 sensor but to be used for data logging equipment. The placement of the bung is also further aft on the mid pipe closer to the engine. I'm not sure if the the original O2 sensor would be long enough to make it that far back to connect. I had to send one mid pipe out to get it plasma cut and get another O2 bung added. I need to install both O2 sensors and these pipes don't have that capability the way they come from the factory. On a side note, they do come with mounting hardware and some aftermarket gaskets which is a nice plus.