I'm swapping the blown engine from a 2003 350z with a 2006 vq35de. I'm going to use the harness from the o3 so everthing will pin the same to my ecu. I was wondering if there is anything I need to replace while I have the engine out? I'm rebuilding the front end and replacing exhaust while I'm already under it. Thanks for the feed back.

 

Ecu, key, ignition switch....

 

Front a rear main seals don’t leak all that often but they are much easier to replace when the engine is out should you need to. I’d also have a look at the valve cover gaskets to make sure the tube seals aren’t leaking oil onto the top of the plugs.