How to stop my car boot vibrating?

polyurethane foam the plus is it is not terribly expensive.and will make panels like concrete.......spray it into the hollow parts of trunk lid and behind interior panels the downside of it is it can very messy.....so use carefully and not too much all at once in area...until it stops expanding...if more needed then add. add ..there is sound deadening material called Dyna-mat.....or other companies call it something else ....it is a hardened tar and asphalt based material with an adhesive on one side...to attach to panels that vibrate....

You have to use a material to deaden the sound. I cant remmember what its called but basically you have to mould the material round the boot of your car with a heat gun and it sticks. It could be your number plate though.

it may sound daft but have you checked your wheels are tight ,tyres are OK no suspension faults etc i think u should fix the vibration before you go any further

It could be that the bass is just too much. With time it could affect your hearing. Try to turn it down the bass setting a little.

Is the sub facing the boot lid? Try turning it round so it's facing the rear seats.