I have a 2003 G35 sedan 6 speed and I have seen a couple of coupe engines for sale and I don't know it they would fit my car. Does anyone know if they are interchangeable? I guess that goes for the transmission as well?

 

This has been disccused MANY times, try the search function!

A straight swap would be a VQ35DE, People have been able to successfully put in Rev-Up motors with success, but lots of wire harness modifications.