There is NO such thing as SWAP KIT.
If you don't want to hussle with fabs, I recommend buying a COMPLETE engine, transmission and body wiring for the 350Z. Hook up everything as they should be in a 350Z and then wire up the accessories such as door/wiper/lights to the 350Z wiring.
You will need to replace the 240sx techs with Maxima (VQ35DE) techs of course.
At that point, the only thing to fab will be motor mount, Hood (or) Exhaust manifold, drive-shaft, transmission mount and shifter linkage.