Hey, I've recently installed a double-din head unit in my wk statesman without knowing that you lose date and time etc. At first I was really disappointed but I've started to work around it.
Firstly, I've been told you can get holden to program the centre console screen to show the correct date and time. I'll find out for sure on the 30th November as I'm taking my car in for a service then.
Secondly, your awesome double din head unit should be awesome enough to show the time and volume etc. on its own screen. This means you'll just have to deal with the top screen displaying the wrong date and time for the time being.
Thirdly, you do lose steering wheel controls, but jb sell a wiring kit which they charge around $297 for. This will make them work. It's really expensive so I've decided to go without it until I finish my sound system.
Despite the loss of controlling date and time, plus steering controls - you get a second screen to display it for you, you get bluetooth, you get ipod connectivity, you get gps, you get a better equaliser, you get a dvd player. Above all, the amount of losses does not compare to the amount of gains. I personally think its worth it, because the steering controls can be fixed, and you wont be disconnecting your battery once you get your sound system down so yeah =].
And just so you know, don't get your head unit installed at jb. I got jb to install my head unit and when they did, I lost my parcel shelf speakers - BUT me and my mate got everything re-wired and it works fine.
