6x 10ohm 10W resistors from Jaycar, some wire, some heatshrink, a diecast ally box.
I used one big fat power feed into the box, split to the 6 resistors with 6 individual wires out. Traced back the common injector power feed in the loom, cut it and fed to the resistor box. I also traced back all the injector earths, fitted a 6-pin plug and made a whole new injector harness with brand new Bosch plugs.
Some people wire the resistors into the harness and be done with it, personally I think that's well dodgy. I put the resistors in a stack of 3x2 with gaps in between and ally shims top, middle and bottom. I used thermal paste on all contact surfaces between resistors, ally shims and ally case. Just make sure you heatshrink all exposed wires so they can't contact the case.
Thread: http://www.skylinesaustralia.com/forums/topic/62674-gtr-injectors-into-rb20det/page__st__100
Pic of my resistor box..