Rear Parcel Shelf Vibration

[kfsn1]

I can report I took the rear heart and guts out of the car. I found the sponge padding under the rear parcel shelf to be gone or minimal everywhere. So, I padded it all underneath with cut up sponge pieces (kids bath toys!) stuck in with sticky tabs. It has reduced the vibration massively but I can still hear it a bit. I think I will just have to notch the subwoofer back a little bit and it'll be fine. Thanks gents.