I'd personally stick with an Avital, or Viper unit. Directed offers a great product and they have Xpress kits that work with a multitude of vehicles. One issue is they won't warranty anything if you install it yourself but if its from an authorized installer, they'll bend over backwards to make it right with you should an issue arise.

BTW, for those that are looking at this for their Crossfire, there are NO kits out there that are plug and play and if anyone says they can make the kit work without needing one of your keys, they don't know enough about the car to warrant them doing the install so don't walk, run! LOL

Hope this helps!