Newbie!

[Giles2606]

I have searched all over the forums and learnt a lot from all the questions and answers posted here, but nobody seems to be quite doing what I am after.

I have just bought a '99 523i (this is a Swiss model) it has the stock radio/cassette head unit, no DSP, 6 CD changer in the boot, and the hi fi speaker option.

I have an iPod, and I would like to connect it to the car. Currently I use a cassette adapter, as this was the quickest fix I could find, however the sound quality sucks, and frankly the sound quality of the whole thing is poor.

Alpine are bringing out what I think is the ideal iPod adapter, which controls the iPod from the headunit, all track information is displayed on the head unit, the iPod can just go in the glove compartment, and all songs on the iPod can be accessed from the headunit... no more dangerous staring at the iPod screen trying to figure out which album to play next :-) see the link below:

http://www.alpine-usa.com/products/l...h_kca-420i.htm

So what I want to know is, how can I change the stock head unit on the car for an Alpine headunit (eg CDA-9835R) in preparation for this coming out. I am not concerned about the final look of the thing - the stock head unit is not to my taste anyway.

What would I need - dashboard adapter; wiring adapter; connection to cd changer; ???

My issues/questions are:

The shape of the stock radio is not standard, so some kind of adapter needs to be found (Crutchfield, Metra...)
The stock headunit is not really a headunit at all... and this is where I get a bit lost :-) but for the sake of simplicity I will call it the head unit - it appears to be in 2 parts - the top cassette player piece, which can also be swopped for a CD player; underneath this is the display, which in my case allows me to choose the cd in the changer, and operates the cassette player, tone controls, shows the radio station, cassette side playing or cd no and track.
I get the impression that the headunit is somehow connected to the on board computer, I'm guessing this is not the engine management thing, but rather the outside temperature, trip computer etc.. People also talk about the MID (what does this stand for ?) I do not want to lose the on board computer functionality.
The radio seems to be in the trunk, next the amp and cd changer.
Its not very obvious how the stock headunit comes out, I have read some descriptions, but mine seems more firmly attached than just the nut behind the volume control.

Is there a way of replacing the entire headunit, keeping the OBC functionality and connecting an iPod?

OK, so sorry for the long post, looking forward to your replies!

Thanks, Giles