At the moment I've got the Karma plugged into the AUX in on my Sony Headunit, sounds really good, if not a little quiet, I have to run the volume at 28 to get it anything like.
The Karma sits neatly in the tray under the headunit in the Smart. This is only a temp pre-empeg solution. A custom Dash-Facia is currently being made (by myself).
Although the incar Karma is an easy solution, I'm a fiddler and probably only listen to about 5% of my tracks in full, I spend most of the time skipping tracks or adding new ones, I can't do that very well while driving with the Karma, with the empeg it's easy.
And I think the empeg still has more cool factor
Cheers
Cris.