Just wondering if the 2 cat pipes and first Y section of the exhaust are interchangeable between coupes and sedans. I'm looking at a '05 sedan. Thanks in advance

Yes, they are...midpipe and headers are as well. Only difference is the muffler. Also it is the same for the Z, minus the midpipe and muffler. Midpipe is 6 or 8 inches shorter. I'm currently using a y pipe from a coupe on my 06 sedan (my sedan one got damaged from being too low)

They are not interchangeable. The muffler end is different and the Ypipe clearance is different as well

Thanks for the response? What about the header pipes though? Can I use one from a Coupe on a sedan?