Replacing Head Unit

[SF H2]

NJ H2: I am about to have an Alpine dealer install a system similar to what it seems you have (but I've opted for a fixed screen). Where did you place onstar, in the center console as Detonate did, or elsewhere? How did you get the wheel controls to work (the installer told me he won't guarantee it and that it has only worked off an on when he has done it in the past)?