You can get a truck 5.3 or a 6.0 and mod it and make the same power or more then a ls2. you can use the truck or camaro harness and pcm. But with modification making the harness like a stand alone and removing the pats system from the pcm. Also you can use a megasquirt set up. You will have issues getting the factory gauges to work, The gm tach signal is the same as a 4cyl. So the tach will be off on a factory 6cyl car like your 350z for example. Also depends on what accessories you want to keep a.c/ p/s. getting it to fit and run are the easy part.