Good luck with the GTR mate.
Good cars when they are taken care of. I've seem alot in shops though (more than Mitsubishi's).
They can be somewhat problematic especially with the oiling system (I've seen quite a few go into the shop for full rebuilds due to oil starvation).
Keep in mind that they have poor oil return from the head to the sump.
There are a few mods you can do but they are not fail safe.
Be sure to keep us up to date with how you go.
If you want to go all out on the GTR, do what the big boys do and buy a RB30 block with an RB26 head. 3.0 Litres of mayhem.
Here is a helpful link:
RB26 oil problem