You can replace the entire front harness on first gen cars without too much difficulty. You will have to be creative in routing the plugs through some tight sections, but it should not take too long to do. 1/2 day max if you are carefull and have good ability. Start from the firewall plug and work your way to the front, then to right. It's pretty self-explanatory since it is almost imposible to plug something into the wrong place. The ampmeter will be the only new item to install that will not be on the original harness. This should go to your voltage regulator. Ask your supplier to provide a diagram for proper attachment. To remove the firewall plug you must loosen a bolt that is in the center of the plug on the engine side of the firewall. I believe it is a 3/8" hex head bolt. You will have to pull the engine and light harness together since they interlock. Use some silicone grease on the firewall plug and all other connections when re-installing to reduce corrosion. M&H is a good source for these products and is a sponsor of this website. If you are considering going for factory gauges then go for the correct harness. However, you will lose many features and may cause major damage if you try to run a gauge-type light harness with only warning lights.