2011 srx adding nav radio

[jthomp4373]

Hi i am in the process of adding a NAV head unit, pop up display and unlocked silverbox radio. I expect that I will be missing a harness for the pop up mechanism from the radio, and probably a VSS wire. Since my SRX already has BOSE, XM, Onstar and everything else is it safe to conclude that there is probably a connection between the silverbox and the display, and not much else? Has anyone else done this without the custom harnesses that are available?

Thanks,
John