I installed the Icelink Plus in my 2002 325i about a month ago. Installation was pretty easy, disconnect the battery, pop off the wood or aluminum trim, remove the CD player, and connect the Icelink cable. There were some issues with the Icelink Plus at first where you would sometimes plug in the iPod and nothing would happen, so you would have to disconnect the Icelink from the CD player, but that has all been resolved with the latest update. I love mine, it is the best iPod adapter I have seen.
I highly recommend it to anyone looking to connect their iPod to their car. You can either use the Icelink's interface, which uses 1-5 as the first 5 playlists on you iPod and 6 goes into the Icelink setup, or you can do what I do and just use the iPod interface. With the iPod interface, you still have control of the iPod through your cd player and steering wheel but the iPod just displays its normal screen as if you were listening to it with headphones.
The ability to update the Icelink is a big plus in my book. As with the prior issues, the Dension team worked really hard to correct them. The team itself always answered my emails and are really friendly and informative on their message board. I also heard a rumor that they were looking into having the OEM cd player show song info, but that isn't a big deal for me since the iPod is right next to my CD player. Also, if you have any ideas or suggestions that you would like to see on your Icelink, Dension is up for suggestions and welcome ideas.
The sound quality is great, just like a CD. Although, you will have to go into the setup menu and turn down the amp in the Icelink because with the amp at 4V or 2V, you get some distortion, so I turn mine onto 1V, which is the same volume as my radio. Other than that little detail, which you only have to do once, the sound is great.
The ability to use the steering wheel controls is a big plus, too. You can even navigate the Icelink menu through the steering wheel, which is nice if you are driving and need to change some setting.
If you use the Dension interface, when you turn off the radio, the iPod will just say, "Ok to disconnect" and will resume from your last song if you turn on the radio. With the iPod interface, when you turn off the radio, the iPod itself turns off. The iPod will turn on when you turn on the radio, but will be paused. I take my iPod out of my dock when I leave the car and lock it in my glove box, just so it doesn't attract attention.
If you aren't good with electronics, you can still install your Icelink. I have never installed a cd player in a car before, but I learn things quickly and I think anyone can do it.
If you want, I could take some pics of how mine looks and post them. Other than that, if you have the money, get one and get a dock connector. I have the one that fits on the side of the cd player, so the iPod is right next to the search buttons on the cd player.