they are exactly what I would buy if budget was not an issue. They are a thoroughly developed and tested caliper with an excellent range of pads available.
Well that is pretty much how I felt about the g4 ones, there is a little more travel but, to me, nowhere near enough of a difference to go through the pain of a master cylinder change. The pedal is still perfectly progressive and reliable, you very quickly forget what it used to feel like and it becomes normal
BTW re potential bias changes....on the street its not an issue unless it is really screwed (eg 1 tonne ute in the wet). On the track it depends on what sort of suspension etc you are running. On very firm suspension you would benefit from more rear bias, even from stock. But under any sort of normal suspension the static weight is around 66/33 front in a GTR, and that moves to more like 80/20 or more (close to 0 sometimes) under hard braking. With that sort of weight you do not want rearward bias.