yes its possible if you have a base sound system with no amps etc. it has been confirmed to work in a few cars. If you have an oem amp however there are only a small handful of cars that have this working with extensive wire splicing and other methods. But in most cases this is not plug and play if you have an amp features might not work and they are still figuring this retro mod out as they understand the computer. The biggest difference is in the pre 08's we used a can bus computer in 08's they actually changed the computer.
So i would say prob in your case go with the rec nav unit, or go aftermarket because you having a c prob means you have a premium sound system and the my gig will not work
This is topic of many a discussion here. Some have got it to work sorta. From what I've seen it is not confirmed that many of the other features will work, UConnect, etc...
I've decided to stick with my REC unit even though I wish I had a MyGig.