I just installed the AVIC D3 in my 07 Ram hemi QC _myself_. It isnt that hard.
Call up sonicelectronix.com, and they will sell you the accessories you need. There is a Schroth harness that plugs into the factory harness and solders to the leads coming out of the D3.
They also hae a Schrothe mounting kit with a mounting ring that fills the extra space around the d3. If you dont have the factory navigation bezel, you can buy one on ebay. They have em in differnt colors with a sqaure cutout.
You also need a metra brand antenna adapter that lets you plug your factory antenna into