Its not that expensive depending on what you want to do Ive spent probably around $150
I went to my local auto sparky to get some ideas A good helpfull guy who is into older cars.
Most important thing I think is to use good quality materials and tools & with any soldered joins the shrink wrap is the go. With the late model plugs (CA18 injectors cam angle sensor ect) you can get new pins. You need a specail tool for this I basically got everything where I wanted took the loom in and borrowed the tool removed old cut wiring and hook the old plugs upto new wires.