Building a motor right now for that exact swap except for an allison behind it. As your friend has found out the wiring issues are interesting as the gauge and other signals are sent over a signal wire to the stock dash in the 03 and up this presents many challenges in the areas of all instrumentation and issues such as ac signal from the heater and ac controls. Wait to start, water in fuel light, tach signal. Temp and oil gauges are easier by adding another set of sensors. If you like you can have him e-mail me at -- email address removed -- tell him good luck.
Brian