Hey, i just recently purchased a Brand New 06 Mini Cooper S Chilli for my First car ever

, now it runs perfect on normal highways and city driving, but yesterday i noticed with the Sound system off as soon as i get on the back roads near my house i get quite a noisy rattle coming from the drivers side door it seems, any ideas ? also i noticed with my Harmon Kardon sound system the Rear Left passenger speaker has a slight rattle, but if i put my hand on the edge of the speaker cover it goes away, any ideas ?
I dont want have have to take it back 2 weeks from rolling it out of the dealership
Cheers
Pnut