I've had this car since September. It's an '02 WRX Wagon, with full exhaust and some brake work. When After I have been driving around for a while, and I get to a bumpy road (thank you New York), I sometimes hear this noise. It sounds like glass bottles clanking against each other, except a little more metallic. I'll have to try and get it recorded, maybe tonight If I can recreate it. Sometimes it happens when I get home at night and shut my hatch, or the rear doors too. Actually that's when I first heard it, at night closing my trunk. I though it was the exhaust, as it does sound like it's coming from the rear of the car, but the exhaust seams nice and sung. I really have no I dead what it could be.