I added one to my GT at the end of August. It took me about 3 hours to do the entire swap, but I took my time. First disconnect the battery. Remove the knee bolster (under the steering column,) then remove the dash bezel, and unplug the foglight switch.
Some people soldered the splices together, but I just used butt connectors. You will need to splice into a orange/black wire on the back of the radio harness, the dark green VSS wire on the back of the instrument cluster, and the tan wire from the Data Port Connector (where you plug in an OBD plug) I used splice connectors from the Auto parts store, it was easier than trying to strip casing off such a small sized wire. The VSS wire is the 2nd one in and its dark green on the tan colored plug on the instrument cluster.
I ran up the wire from the 3 spliced locations to the Analog connector. Pop out the analog DIC and cut out all the wires. Then just start butt connecting the analog and spliced wires you ran to the Digital plug. Heres the list I used to connect the wires.
Automotive Forums .com Car Chat - View Single Post - converting analog dic to digital drivers info center
Once the wires are all spliced, connect the battery, plug the connector into the Digital DIC, make sure everything works, and lights and dims like it should, then if it all works, snap the DIC into the spot on the dash, then put the bezel back on.
Heres some more pics and wiring diagrams from a site that I found.
http://www.automotiveforums.com/vbul...d.php?t=765080
Any more questions just ask.