I don't think the RB26 will bolt straight up to your engine mounts. And i think you will be needing the sump from the rwd RB30, but i don't know. If you're going to spend the $5000+ on the engine, you might as well buy a skyline gearbox from a GTS-t 2.5 and the 4.4 lsd diff too. And a computer. I haven't done this before so i'm not the best person to be talking to about this but i'm not sure if you'll be able to do it for under $10000. You'll need an engine, sump, fuel pump and lines, surge tank, computer, suitable brake upgrade to make it legal (in aus at least), gearbox, diff, new underware.... Good luck : )