I am trying to install satellite radio in my 03 CTS, spliced the harness and got all the way to having someone with a Tech 2 programmer go in and try to 'enable' the feature, but the feature selection just wasn't there. I found out later, of course, that my radio is one of the early 2003 ones made in Germany that has no firmware installed, so the feature was never built in. Now I'm going to replace the head unit with an 04-05 unit, but I'm having trouble distinguishing the Bose from the non-Bose units on ebay, and the sellers seem to have no idea.

So...does anyone know how to distinguish the units? I have the Bose option (U2S) in my CTS, so I need to install a Bose head unit. There seem to be different part numbers, both GM and Siemens part numbers, between the years and models.

All help greatly appreciated, as always!