I would just remove the new style harness and install the Lucas style. The hardest part would be mounting all the Lucas components on the firewall and hiding the existing holes in the firewall.
If it were up to me, I would pull the dash and the firewall and make a new firewall to go with the OEM style harness. If you were prepared, you should be able to do it in a weekend.
I've wired up a number of CSX4000 cars, feel free to ask any questions.
