Yep, the 556UW is the one you need.
As for installing it, try to find a Viper/DEI dealer that has a good installer, and then just maybe you'll get lucky enough to find someone that knows what they are doing.
Im not going to get into detail about the crap work I've fixed from "so called installers", even from big name stores... but some of the work I've seen and fixed, the "installer" should be shot in the head for doing that kind of work to a car!