You can put any turbo on an rb25. Just depends on what you want to use the car for and how much power you want. Hypergear stuff isnt crap and props to them for making the choice easy for skyline owners when it comes to setups.
The reason why garrett and precision dont spend so much time developing a turbo for the 25 is most likely because they aren't aiming for skyline owners but moreso aiming for the entire performance/turbo world.