Well if you already have the controller and gauges go with the ones that are available from site sponsor PRG. He will be able to help out with any questions you have and get them to you in a timely manner.
I have the Roadmaster Active Suspension and love it so far, though I haven't done a distance tow yet with the Travel Trailer because I just got a new rear-end in my truck and I am waiting on getting the trutrack installed. Once that is done I will be taking the toy hauler and quads out for Labor Day for sure. The nice thing is they stiffen the springs but not the rid and help with cornering and stopping also.
www.activesuspension.com for more info.