OK, finally got all the stuff I needed:
- a new Alfa GT
- an old Alfa 147 factory radio from eBay
- a Bortesi AUX adapter for older Alfa 147's
- a double-DIN adapter to mount both headunits
- my old Empeg

The good news is:

- it works!

The bad news is:

- the sound s***s

The Bose System in my GT is not so bad, much better than most factory
installed systems. It's impressive to hear so much bass from a little 13 cm
woofer, nicely hidden in the trunk. But there's not enough power to keep
the sound as it was in the showroom when you start driving.
And the front speakers are so much worse than the Canton's I had my 156.
They look like compo speakers, but the tweeter in the door is fake, the tweeters
are mounted on the 16" speakers coaxially.

But then the real trouble starts: I knew the old 147 factory head unit
wouldn't play MP3 CD's, but hey - who cares? But what I didn't know is
that the sound is much worse too. Maybe the equaliser is badly adjusted
for this car. But the Alfa/Blaupunkt factory headunits have a fixed EQ
setting if they detect a Bose System amp.

But the real problem is the sound quality degredation introduced by the
AUX adapter and/or the CD-changer input it is using.

This sort of made me give up.I have little hope the Alfa iPod adapter
will be much better, as it mostly works the same way.

So I just made an appointment with my local installer. He will rip out
the entire Bose System and install an old-fashioned amp and speakers,
so the Empeg can become the main headunit.He will connect the
factory headunit to the AUX in of the Empeg, so I can still listen to
CD's.

If all is well it will just be ready for the next Empeg Meet!

Pim