If you're asking what the big difference is between a 3rd party cheapo harness and the more expensive Honda wiring harness:
1) the Honda harness isolates the truck electrics from the trailer electrics so that a failure of one won't affect the other.
2) we've had numerous reports of electrical issues here at the ROC which have finally been traced back to the installation of a 3rd party wiring harness. Some have had better luck than others using a 3rd party harness. It may well depend on whether or not you live in a dry climate vs a humid climate. Or not. Hard to say.
If you don't have a trailer hitch, you can get one like the Curt 13385 (a lot cheaper than the Honda receiver). Add the etrailer L-bracket and the Honda wiring harness and you're golden.
http://www.etrailer.com/p-18140.html
Make sure you order the right p/n harness for your 2006.
Trucks mfg prior to 8/24/05 do not include the reverse circuit, which could be an issue for you.
There are tons of threads here about hitch and harness installation. Ask away if you have questions.