John, it wasn't a premade adapter. I googled 8-pin DIN female and bought one of the chassis mounts.
8 Pin Din Female Chassis Mount - VETCO.NET
While you are connecting the wires to the above part, reference the diagram on the back of the stock head unit to make sure you are connecting to the right pins. Once you have that part, you just spice the appropriate wires from the new head unit, slide them through the slots and bend the wire back and then use electrical tape to tape them into place, being cautious to cover all the actual wire so that the wires don't touch (very tight fit). Special issues are: my Eclipse unit had a wire marked "Control B+" which goes to the RMT node on the DIN. All the other wires match up except the speaker grounds. The stock unit had a common ground for front speakers and a common ground for rear. After market has one for front left, one for front right, one for rear left, one for rear right. Due to the tiny slots on the 8 pin DIN female, I connected one of the fronts to the other front near the base of the spliced wire and then slid the top of the exposed wire through the slot. Ditto for the rear. Then taped all the wires together so that they wouldn't not have much movement and plugged straight into stock DIN.
For the other plastic connector, I cut that off at the plastic connector. NOTE: Before cutting that off, write down what each wire is based on the sticker on the stock head unit. Unless you are going to install another stock head unit, that connector is worthless IMO. Alot of people have a problem or worry about cutting this off. Once you cut off the connector the wiring is pretty straight forward. All the aftermarket wires are labled and you have the diagram you just made with what the stock wires are. Then it's a simple matter of splicing, connecting and taping. NOTE: If you do not disconnect your battery, you will blow the fuses that power the radio (dome, winshield washers). Nothing else bad will happen.
Final NOTE: If you want a very clean, neat setup, this head unit is probably not for you. I do not even have it screwed in on the inside of the dash because the brackets (even stock ones) will not slide back far enough for it to be screwed into the stock holes. It is hard to tell from the pictures also, but the unit sits at a slight angle, aimed toward the driver (which is awesome actually) but that angle and the width of the unit prevents it from moving anywhere. But the unit doesn't move even a tiny bit. I have driven it a few times since and gotten on the throttle pretty good and it doesn't budge.
