[sav10]

Have an M240i. When I open the boot and let it swing up the car shakes. Dealer says this is normal but just wanted to check as have noticed doesn’t do it on a car in the showroom.

[RockCrusher]

Originally Posted by sav10

Have an M240i. When I open the boot and let it swing up the car shakes. Dealer says this is normal but just wanted to check as have noticed doesn’t do it on a car in the showroom.

With both my M2 and my 230i the trunk lid (boot) are supported by some kind of struts that also act to prevent the lid from going up with too much velocity/force.

However, I don't rely upon the struts to prevent the lid from going up with too much velocity or force but keep a hold of the lid as I move it up and fully open.

IOWs I don't let the lid swing up/open on its own.

My cars are too new to have these struts worn out -- I did wear out the front and rear trunk lid struts on my Boxster and a bump on my head told it was time to replace the struts...

But in the case of your car one or both struts could be defective.