Need some quick help. I have the D3 currently installed on my new vehicle. Love it, but hate the nav discs I have to load and the fact that there is no hard drive for me to store music. The dealer told me the D3 didn't use nav dics and that it had a hard drive. Now that this is all coming to light, well the guy is giving me the upgrade to the Z1 for $200 if I want it. I love the bypass and being able to watch DVD's in the front seat. What should I do? Stick with the D3 and buy the ipod adapter or get the Z1? Pros and cons of each would be nice? Thanks