i had that same diffuser on my 350z and everyone loved it, especially me. it really really setoff the back end of the car. i know exactly how it mounts and its not going to mount properly to the 370z, maybe if you cut off the oem section around the tail pipes including the fog light area.
i am retarded for not checking it out when i had my 350z and 370z side by side and had just removed that diffuser to sell it.
i dont like the end pieces tho, and i didnt put those on.
mine;