Man, that sucks, but at least you still have your car. Mine was stolen a few years ago now and they got away with over 10k from audio 5500, Rims/tires 2k and I had a shit ton of movie CDs and music CDS. close to 3g in just that. I only took my cutty to work 10 times in the 2 years I had it and the 1 day I was late, I had to park outside the fence as there was no where else to park, it got stolen and taken to the next city, and was gutted! They found the car beat to hell............so not only did they get all my shit, the beat and ruined a perfectly mint 85 Cutlass with only 86k on the clock. Car itself was easily worth 4k with out that shit in it.
Sorry to hear your about your situation. Deffintley sounds like an inside job. I imagine it was a ma and pa type shop, where you were getting your car fixed?