Got Double din??? INFO

[mini_dub]

I really fancy one of them double din headunits for my 5.5 but have a few questions before i make my mind up!!

What would i have to buy/change on my dash to fit one? how hard are they to fit
what is stopping some little ****** from pinching it?? do they have a face off or any sort of secruity??
which one to get?? i dont want to spend the earth on one but it needs to be able to run/charge an iphone, and i would quite like one that you can set a wallpaper and shows ablum artwork off the iphone also dvd!!

and anyother pros/cons would be good

~Cheers

Chris