Replacing the main harness on a 3L

[SpinningMarkVIII]

I am interested in buying a 3L Contour but the main harness ahs been hacked up some aparently. It was done by a shop so I am not sure of all fo the details on this. How long would it normally take to dos oemthing like this, does the main harness bolt/plug in at the firewall so that I could simply unbolt it and plug in the new one and then plug in everything? Is there anything in the compartment that is nearly impossible to reach?

 

[96BlackSE]

The engine harness connects to the PCM at the passenger side and runs by the firewall between the engine connected to the 2 rear valve cover bolts and then connects to the main vehicle wiring on the driver side near the brake booster/master cylinder assembly... The engine harness can easily be swapped while the engine is in the car all the connectors are accessible some of the more a PIA then other such as the alternator due to locations but its a fairly easy job...
Just make sure you get the right harness for the right year... Whats hacked up on the harness anyhow?