I recently stumbled upon a cheap used OEM Nav head unit online (PN: 10391240) and figured I'd give installing it into my 2007 Base GP a go. the unit was apparently pulled from an unknown year(04-08) and unknown VIN GP. Its my understanding that the Nav system requires an AMP which is fine because I fully upgraded my sound system to the monsoon system with the trunk AMP and 9 speakers. The VSS wire will be a pain in the butt though I do think I understand what needs doing. I plan pinning it into the radio connector, running it out the firewall boot below the glove box and pinning it into the intended connector C2 port B11 in the fuse box which is empty but internally connect to the VSS circuit. I do have a few questions though.

-is there there a pre-made harness I can buy to connect the Nav to the VCIM? assuming the wiring diagram below is correct, it appears that I simply need to connect two shielded wires (PNK and PNK/BLK) from the radio to the VCIM since I do have onstar. I have checked my VCIM under the dash and there is no connector in the J3 port which I belive is C3 on the diagram. I found this eBay listing, are these the connectors I need and can I make this work? NEW CHEVY TAHOE SUBURBAN GMC SIERRA YUKON DENALI NAVIGATION VSS WIRING HARNESS | eBay

-is ACDelco PN: 15821030 the correct antenna for the Nav? from what I've read online the wire leads are way to short to install the antenna in the factory location. I've also read there is a corvette antenna that is identical with longer wires but can't find a part number.

-will the Nav DVD be required after the VIN relearn at the dealer? If so which version of Nav DVD do I need? they are expensive, some more then I paid for the Nav unit itself and I don't want to get the wrong one.

Any tips or advise will be greatly appreciated.