I can guarantee you someone has done what you are trying to do. And I would guesstimate this is going to cost a pretty penny. But let me ask you why are you swapping one six-cylinder for another one? why not move up on the food chain and opt for more cubic inch, there is only so much horse you can squeeze out of a small displacement motor. If I had the money I would put an GM LS1 or 2 in it instead there an all aluminum V8 and can make way more torque and HP than a VG or VQ can ever dream of. Plus how many guys can say they've got a V8 in a 350z?