HI Ben,
You might want to get those tyres first thats for sure.Do not do disks without pads to.Try bendix advance for every day driving or ultimates for track days.Beware, ultimates wear quickly but stop you every time and they are cheap.Window tinting will be ok under warranty.For the moment I doubt you will need a piggy back as you have yet to explore electronic boost control.12lb of boost will give you a woody, trust me.Contact gR33dy when your ready, he may be able to help.
I`m confused,you want a GTR but you buy an auto,hmmm......
Honestly,two of everything will cost you dearly.Have you ever changed a GTR gear box?Exxxxxxxpensive.They are great cars,don`t get me wrong,but for the every day street driver you should appreciate what you have.Be honest,after you spend 30-40 thou` on your GTR will you really use it the way it is meant to be used?Personally I would rather have a nicely modded GTST and not cry like a baby when I blow it up.(if).99% of the time you will be in the traffic with a nice fast comfortable car laughing at guys like me in stiffly suspended heavy clutched manuals.