I've heard the same thing. Which is why I'm hesitant about ordering a Procharger from them. It's cheap, and I get the most options, but don't know if I'm willing to lose out of $4000+
And a couple of other sites: http://www.moranav6racing.com/ http://www.supersixmotorsports.com/
No, not all V6's need the additional harness. My 05 V6 has the plug going into the blank switch like Roddy. I remember reading on another thread where depending on the year, you may not have the plug. I want to say it started in 08, but I'm not entirely sure.
Check the end point in the wiring for the release. I'm not familiar with the system so I don't know if there's a solenoid or anything like that. But if you're not getting power there, "trace" the wiring. There may be a break or something. You can also try replacing the wiring entirely.