yeah, it's pretty easy. When you open the trunk, stick your head in it and look up. The first thing is to pull those metal slide clips out. They pull in the direction of the rear of the car. Then just pop the plastic tensioners out. You can use a pair of wire cutters, to do this. Just slide each side of the jaw under the plastic cap and pull straight up. They pop right out. Then I would use insulating foam, felt pads, or a towel, or something light and that will stop that from being able to bang on the top like that. You might even want to use some dynamat or something? Just an idea anyway.
Hey thanks smooth, I'm going to try and do that this weekend, I'll let you know how it goes.