I have seen the turbo and thought i would help out and clear a few questions up,
It is oil cooled only, but it is internally gated, some weird kind of internal gate, with a circula dump pipe flange.
so will be a direct bolt up for rb20 25, but not for the dump pipe.
Turbo looked to be in good condition just a little dirty, This seems to be a great price for this turbo,
Hope this will help the sale, good luck mate.