Thought I would share my experience with these front pipes, with same facts, negun list these as 80mm and $ 812 aud. They are 70mm (2.75") outside diameter and 60mm on the dump pipe end. They are stainless mandrel with the only welds being on the flanges although larger than normal flanges on the cat back end still the normal 87mm nissan bolt spacing (mig not tig) nice thick flanges that are the correct orientation for oem dump pipes to off the shelf cat back (oem orientation). They have no hangers. They have nf320 badge plates welded to them that state left and right. Now being 2.75" the cat choices are one, 200 cell magnaflow. I ended up getting 2.5" cats that need to be cut back to 70mm then welded in, they bolt up to 2.5" cat backs and I would imagine 3" catbacks. Fitment is good in that they bolt on and clear everything, ground clearance as in how far below the chassis rail is bad like 30mm below chassis rail (maybe my engine mounts are sagged).