The kit supplier should be your best advice here...
Mostly depends on the motor you're using these days, if a donor motor is used it will need its loom and computer etc
"Painless" do custom wiring looms for such things
"Sideshow" on this forum is the man
Peter "Chunky" Hancock is very good -- but only does show quality stuff
That said, if you're handy at electrical stuff then go for it, just remember that a little knowledge in this is dangerous, then you will need one of the guys above to untangle the bugs
2c