Hi chandd,
If you whip out the climate panel control unit, you'll see a load of connectors on the back of it, including one with just 2 thick wires in it. These carry a switched feed.
I'd only splice in (using soldered connections) after you've confirmed the feed with a meter - better safe than sorry.
As to earthing the system, I'm not familiar with the particular models' wiring loom, so you need to check with Parrott ideally. I need to fit the 3000 evo kit still so if you get around to it before me, if you could post how you did it I would be grateful! Cheers Lamby.