Eric, a company called Martel Brothers, who sponsors the Sport Trac Web Site (sister site to this one), is arranging for special group pricing for Sport Trac Web Site members. We are about to do an evaluation write-up of the Roadmaster system on a Sport Trac for the web site.
Rumor is that the Roadmaster system really does work. I'll know more in a couple of weeks. If it does work as advertised and you want one, let me know and I should be able to get you the group buy price that the sponsor is going to run. I don't think they'll care that you need one for a Silverado.