of course it can step out....dont forget its not a full time 4WD car. R32's its easy to remove the switch and have RWD mode only. Also if you have an HKS ETC, Grid Dancer, etc. you can also go RWD mode. Just remember, GTR's arent drift cars. You want a drift car, buy a 180sx or something similar thats cheap.
Diesel, something for you to bare in mind....can you afford it? By that, i dont just mean afford to buy the car itself. If you buy an R32 GTR be prepared for worst case scenario. Think about insurance aswell.
You didnt specify on which GTR or GTST you were after. R32 and R33 GTST have different motors.
For me, GTST was never an option. I chose a GTR....and my pockets are quite light because of it. But as Manage13 said, it is up to the individual. It all depends on what you want it for.