Plug & Play Units

There are three plug & play units I want to have installed in the future. They are the Tom's LTS, navigation override by Prestigious Society, and the Ipod adapter from the dealer. I just want to know if these devices will work together without causing problems such as shorts, electrocutions, explosions, and fire while the car is in motion (scary thought)! Does any of you have all of these installed? If so, please give me some feedback.
I'm assuming installation would be simultaneous, since they all plug in at the back of the nav unit?