As promised, here are the pictures of the salvage car I had questions about. Apologies in advance for the quality, but it's what happens when you only have one hand to shoot pictures with!
Here is the until-now mysterious box in the wing; I just found out it's the XM tuner!
And here's the Monsoon amp under the parcel shelf!
AAAND (finally!) the mysterious box under the dash behind the radio opening!