is it possible to turn a stock gts-t(like buy new bumpers and other stuff) and make it into a gtr.

Wider alloy guards, different alloy bonnet, new front bumper bar are needed to creat a GTR front end. The GTR has wider rear guards than a GTS-T so that will be a problem for you.

Mechanically, you willhave trouble fitting a GTR motor and 4WD system into a GTS-T unless you have a GTS-4

I see what your saying. I just want the car to look like a gtr but have a decent motor in it. I really dont care if its AWD or FWD.