To my knowledge the cat back is a straight bolt in. My muffler is right where the LR one was and then the pipe goes back from there. There is no resonator since I ordered it without. I like the headers and I put the bungs in for the O2 sensors, but did not add cats because I did not have to. It would be easy for a muffler shop to add them in to the Y pipe and I would suggest some of the thin universal types that Jegs and other shops sell. You could probably do it with one cat before the muffler but that is speculation on my part. I will snap some pics tonight.
72 Series III 109 SW Diesel, 03 RR, 98 Porsche 986, 01 Porsche 986 3.6 L