Anytime they make an interface it makes a lot easier install. Do you need it? Not really, but it does make it easier and if you want to go back to factory (like at selling time), it makes a seamless reinstall, and no one will ever know that you had an aftermarket headunit in there.
__________________ -There are 10 kinds of people. Those who understand binary, and those who do not.
-If we ever forget that we are One Nation Under God, then we will be a nation gone under...Ronald Reagan