Hitch Wiring Options?

[herostar]

Hello everyone!

I'm about to install a hitch on my FX and want to add the wiring because I plan to do some towing...

What are my options for wiring kits?

I've seen the OEM one (about $100)

Has anyone tried this one before?
http://www.autoanything.com/towing/77A3875A3767909.aspx?kc=ffsku

Any other options I'm missing?

 

[Speedster]

Anyone have clarification on this... is there a factory harness hidden somewhere I can tap into elegantly using a product like the OP linked?