Trim Rattles and Vibrations

Hello all,

I always buy used European cars about 8-10 years old after depreciation brings the price down into my budget. I am picky about the sound quality inside my cars both with and without the radio on. I've owned 4 cars from 4 different brands and they all had some level of random rattling or distortion of music.
I understand that 10 year old cars will have these problems. I'm looking for advice on how to address these trim rattles in a cost-effective way. I haven't had good experiences with dealers, independents or audio shops. Is there another type of professional or a book out there that will help me?

You advice is much appreciated!