Not certain if this is the right place for this thread, but given that I found very little information/confirmation on the real world operation of the XCarLink Alfa kit when researching it 6 months ago, I thought this may be a useful review for anyone looking to buy it. I'm not associated with the company at all, just a happy end user.
So, it wasn't cheap, but it works really well. I got the bluetooth kit with it, and was nervous about how smooth the BT process would be, but it's great. For music, I have an old iPhone 2G permanently mounted at the end of the cable (in flight mode), and I used a 3GS and now a 4S as my actual phone in my pocket (via BT). Car has the Bose amp and speaker system by the way.
The cable runs into the blue CD Changer plug in the back of the head unit - cost me $50 to get someone to fit it and run the cable under the steering wheel, put the box near the Diag socket, then mic, BT and main cable all run up the side and onto the front dash next to the drivers door (mic above door). You could easily do this yourself once you figure out how to pull out the head unit using a makeshift wire/tweezer concept device. Bluetooth plugs into the link box, and the button on the little BT box answers calls (and swaps between the two phones if necessary). It automatically picks up my phone whenever I'm in or near the car so that part is seamless (big relief as my old Blueant was crap in this respect). Only issue here is talking on my phone as I'm walking up to the car and the audio transfers inside before I'm in it! Quickly fixed though with a couple of quick taps on the phone audio setting.
Once in the car, music fires up on the 2G, all good. Got up to 8 playlists available or can use manual song/album selection via phone screen, steering wheel controls also work well. Phone call comes in, BT switches audio to my 4s, rings through the speakers, press the BT button and talk via the little mic mounted up above the drivers door, the caller hangs up, switches automatically back to my music. Some people say my voice is sometimes a little bit 'underwatery', but most say they can hear me just fine.
One minor issue is that the volume needs to be high when talking on BT (typically 55-62), but music also needs a high volume level so no sudden major volume music after phone call (but does need a bit of adjustment down if you're not cranking the music like I do). Plenty of volume available for music if you need, but needs to be set much higher than the radio or CD used to be. And of course if you're listening to the radio, you have to swap to the 'changer' in order to hear the phone. I can listen to music on either phone too of course.
I can recommend this unit if you're wanting to use an iPod or iPhone with your older Alfa, and you don't mind paying the fairly high price for it. No more jumping/skipping CD's and good sound quality (although for the audio purist, when you're running the volumes around the 50+ mark, there is a touch of buzz in the background, but any quiet to moderate song level easily overcomes it). Much, much better than FM radio transmitter devices, plus it charges the device as it goes. You could of course use it with just one idevice no problem, either via the cable or via BT.
The fact that it works just as I hoped it would means I'm a very happy camper.