I doubt it was the installer who actually stole the car himsef hes got a business to run, hes proabably got dodgy mates who he gives these dogy c**ts the heads up if theres any nice cars that he works on sets it all up and shit and get a bit of the cut from the sale of parts. Unless u have some hard evidence this dickhead and his mates are doing these operations at the end of the day they just going to get away with this.
Its sucks big time !!! dont go to dodgy places !!!