BMW charge in excess of £3.5k for the retro fit sat nav, so I can well believe the HK price at purchase as an upgrade!
Nick, i'm in Cardiff. There are a few screen options that you can gor for. There is a smaller screen but this is nowhere near as good as *** 16:9 screen. The 16:9 screen is motorised and folds out to reveal either a tape deck or cd deck. The price is obviousuly different, and its somthing to consider if your changing the rear changer to an mp3 one. The 16:9 screen with CD deck cannot play mp3's, so IMO just get the cheaper tape deck 16:9 screen and swap the changer in the boot for an mp3 one with the Intravention Interface. I can even alter the MK4 DVD software to include a nice GUI and female Sat Nav voice!
Ok,
Screen <400
MK4 DVD Computer < £300
Loom £100
mp3 changer £180
Intravention (circa. £100)
TMC Module <£100
If you want the sat nav module (shark fin), they come in at about £100, but there is a cheaper alternative which is a hidden item and it costs a bit less.
TBH, i dont agree with the above post. If the E46 Mk4 DVD comp is set up properly, with the latest firmware, it is far superior to most other sat nav kits availble, and will quite happily travel you all over Europe without making a mistake. It recalculates in micro seconds, and is voice activated to advise you of the nearest fuel station when it detects your fuel going low!
My only reservation i have with it, (and its the only reservation), is that you cant take it with you when you sell the car like you can with other sat nav options, however, you can remove the bulky stuff, and put it back on ebay!!