I don't know why Viper made it only for the iPhone.
As much as it pains me to say it, I understand why they made an app for the iPhone first.
If I were Viper, I would make SmartStart compatibility with a web portal. That way ANY smart phone user could buy their product. You could also access it from your office or home computer. Ahhh, Directed Electronics, when are you guys going to get with the program.