This depends on which 2jz (vvti or non-vvti) wiring loom you have. The 2j loom only needs a handful of wires to make it run. From memory theres maybe 3 wires that need to run to ignition, one constant 12v, and you need to run a new relay for the m-rel which needs constant power and three of the wires out of the body plug. The fuel pump trigger is the hardest as the toyotas run a fuel pump ecu. Using a tachometric relay is the safest way around this.
http://wilbo666.pbworks.com/w/page/37092272/Wiki%20-%20wilbo666 is the best page for 2jz diagrams. Make sure you read and understand the m-rel page otherwise you will always have idle issues!!! Good luck and please make a build thread