i don't know whether we got same hard plastic panel in our domestic market, than in other market.. and whether it's had some soundproof material inside it or not.
but in my cabin, i find it easy to made annoying noise, just by put a coin or keys inside center cup holder, or phone on door handle. and i also need to put my belonging stuff on the luggage with caution or put a pillow so it wont move and hit or knocking the plastic wall......
i also found that every plastic console on the wall is almost empty inside without any sound barrier material inside it.... so if i knock it, it's echoing louder .. so i need put more sound barrier material inside it. hehehe
maybe its some stupid cost efficiency policy on my country..
but the point is i thought a hard panel if it's left empty without sound insulation, it is easy to made a loud noise that echoing when knock or just rattling... its annoying indeed
well sadly in my country vehicle with soft panel material only available on relative high price car.. maybe start from Rp 300.000.000 or around us$ 30.000 .... so hard plastic very common here...
thanks