How can I connect a Radio to a 1988 porsche 944 (Non Turbo)?

Recently purchased a 1988 porsche 944 (Non Turbo) and the previous owner cut the wire harness that connect the radio. No radio was ever hooked up. How can I distinguish what wire is what. Please assist.|||I think this might be hard over the Internet, but, lets try it. My email address is ka3udr@yahoo.com if you have more questions as you go along on this. I think you should do it rather than take it some where, it is always good to learn. The radio that you are putting in, you have to figure out how to mount it. At the hardware stores, they usually see all kinds of metal brackets, and flat metal pieces with holes drilled ever few inches, and duct tape always helps. If the car has speakers already mounted, pull their wires out of the harness, if no speakers are in the car, mount your speakers. I alway tie a lose knot in the positve wire to make it easy for me to find. If it is a new radio it will have instructions, if it is a used one, look around on the case, and you may have to take the cover off for a hook up schematic. Go to some discount store and get a multi meter, usually ten or twelve dollars. Set it on the volt scale, One of the wires that was cut off will have 12 volts on it with the ignition off. Put the black lead on something metal and shinny, make sure the multi meter is set for over twelve volts, start sticking the red lead into the wires until you get a reading off twelve volts. You will get some lower voltage readings from other wires, stray voltage, doesn't mean anything. Most of the wires you won't get any reading at this point. Put a piece of tape or something to marke that one. Turn the ignition swith to on/ accesserey, find a wire that has twelve volts on iy and mark it. Now start the car and with the meter at the same time while still being on that last wire. The voltage should not drop but just a small amount when the starter is engaged, and then the voltage should come up to about 13.8 volts. The radio should have a whole bunch of wires for the speakers and they should be easy to identify. They have such low current on them, if you hook one up wrong, nothing much will happen. Back to the wires with voltage on the, The radio will have a lead comming out of it to keep the memory, find it and hook it to the wire that is hot all of the time. There should be a main power wire that actually powers up the radio, hook the wire that is hot when you turn the ignition switch on to that one. There should be a ground wire, hook it to a shinny screw or bolt under the dash that is going through something metal, plastic doesn,t work as a ground. Speakers will work if you cross the posative and negative wires, but it is better to run + to + and - to -. If you want to track down the wires, put the multi meter on the ohms scale. put the red lead on a wire and take the black lead and start touching the ends of the wires, when you get a full scale reading on the meter, you have both ends.|||You may be able to find a replacement harness from here http://www.metraonline.com