Well, the rear speakers where making a lot of vibration when they played strong bass so I took off the cover(which is a rather big plastic part). Then I saw some "pillows" that didn't seem to serve any service so I took the foam out and with a hot knife cutted it to fit it to the speaker covers (look out for the fumes) and then placed the cover again on the car and problem solved!! Unfortunately my mom thought that those pillows did serve a purpose so she wasn't very happy
