Hello everyone this is my first post. I've owned a G35 for about a year now and I've decided to take the next step and mod some things on it for performance. I'm new to automobile modding although I've done stuff before to my motorcycle. The first mod I am planning on doing is adding a PLENUM SPACER to the intake manifold. But I noticed something about the ones I can find on the website. All of them are made for the coupe or the older sedan version. I have the 2007 G35 Sedan Journey model. And I can't seem to find jack **** when it comes to parts for this car. I won't ever be selling it anytime soon so I have to try and find parts for it. The current mods I want to do are

PLENUM SPACER
"Z"tube and "pop charger" intake mod
exhaust system

Its not much of a problem to find compatible exhaust systems but I would like to know which ones are the best for this car (HP/TQ gains). And if ANYONE can tell me where to find a PLENUM SPACER that will fit my engine and not the older models that'd be awesome. And what is the best way to go about doing the Z tube and 'pop charger' intake mod? Any advice would be appreciated. This is what my car looks like.