I also run a kkr480 on my rb25det and me and a mate installed it ourselves,
turbo bolted up perfect, just had to grind a bit of the exhaust manifold, oil lines bolted up, but i went into enzed and for $30 or so he put new ends on my water lines to match the same size thats on the turbo, then i just chopped the lines and used high pressure/heat hose 2 move them around to fit nicely, and towed car to my mech 2 get dumpipe fab'd up and cooler piping change a little,
comes on hard bout 4000-4500rpm, i just run actuator spring which is bout 1.2-1.3 bar of boost, bit hard 2 control boost in these things, only downside..
but worth every penny, ive done bout 5000-7000kms alredy on this turbo, runs like a dream