The 99 spec tail lamps just plug in electrically.

The wiring harness for the engine can be updated and repaired as required or it can be replaced altogether.
To replace it you almost need the engine out of the car, it can be done with the engine in BUT it's a hell of a job and risky as you might break a wire if not careful, air conditioning has to be degassed and the evaporator box has to come out.

Ignore all advice when it comes to LHD cars and the wiring harness etc, things are set up very differently.

Also if you want a tidy job ignore any advice that says use the LHD harness in the RHD car – it's a mess and does not work out nicely at all.

(The Lab stocks plenty of series two PTUs & plugs and has coil & inj plugs in stock at all times)

Looks similar to the wiring in the new ute at the moment Marty

Maybe we need to have a look at it and see what's wrong, that's a big bit of gear to replace, are you sure there aren't repairs that could be carried out to sort it?