Mate i got the same deal with myself bought a sle cluster but haven't got around to it yet. but i know what the go is first off if you want the oil pressure to work you need a variable sender unit off either an sl/e or a vk i've heard that ford ones work but just as easy getting a vk one. You need to swap that with your one. Secondly the volt gauge will work finewhen dash is pluged in. The tacho is the problem i've asked around and no-one has told me sure that it won't work properly. I assume it won't but i'm going to try it anyway. Basically on the back of the dash the top left above the tacho there's two prongs the horizontal is for the oil pressure unit and the vertical one is for the tacho you need to run a wire to the negative side of the coil for the tacho to work. There's supposedly a plug behind the dash with a brown wire going into it that doesn't plug into anything. This is supposedly what you can also plug the tacho in, I haven't looked yet but am going to give it a bash this weekend. There is also a blue wire that is for the oil gauge.
To get the cluster out there is one screw in the middle at the top ( a stubby screwdriver is needed). then slowly pry the surround out (2 flathead screwdrivers work well) , then there is 3 screws to the cluster then you need to roll it forward and unplug it oh i forgot unplug the speedo cable first before you start i can reach down through the top vent/speaker hole. ok now pull it out forward and to the left and it should be out.
The speedo work in your car?
Do you know if the one in the dash works? you can test it by using the right size alan key in a drill in reverse and see if the odometer ticks over. There's a link in the sticky thread at the top of this section to fix speedo's
Hope all this helps
