Clunk in rear passenger area

[shaman1204]

when driving over rough surfaces going 15mph+. It sounds like its coming from the wheel area. To describe the sound, it sounds like the trunk is bouncing up and coming down when I drive over a bump (it is shut.) Does anyone know what this would be from? I have had the car just over a week and I think it has been there the whole time, but I really noticed it this Sunday for the first topless experience on Lake Shore Drive. I am taking it in tomorrow for an alignment at an indy I was wondering what to look for. BTW, I did get the PPI at another indy shop and it checked out fine. I trusted them because the closest P dealer was 50 miles and they worked on customers' Boxsters regularly. There was one there waiting to be picked up. Could they have missed something?