Here are the things I have already bought for my 05 CTT.

-Hitch Assembly with Foam Pad
-Towing Module/Computer next to CD change in rear right.

I think the only thing left I am missing is the wiring harness and plug/socket for trailer lighting.

Does anyone have the part number for misssing items and cheapest place to purchase?

 

$15 plus S/H - Includes load resistors for if your trailer has LED lights. Will also work with regular bulbs.

http://www.etrailer.com/p-TR20141.html

 

Wiring harness P/n 955-612-506-00 $135 list $108.50 @ Sunset Imports.
7 pin hitch receptacle PNA-955-118-93 $17.50 list $12.08 @ Sunset.
Above prices were from Jan 08 when I did the install on my 06 CS.
Charlie