Patrick, 2 notes:
1. If you want to prove people wrong, why don't you invite them to a mini-meet at your place. That way its "put up or shut up".
2. If your serious about upgrades, may I make a suggestion: Auralex foam wall treatment. No one ever talks about this at headfi, because its primarily for speakers and reflections, etc. But I put up basically a solid wall of Auralex foam that is 2 " thick, in 2x2 foot squares. It is along the 3 walls in the corner where I listen to music. It creates a 'dead' space. It is not optimal for speakers (in this much quantity), because it kills TOO much sound. But this is perfect for headphones, as it makes your environment more quiet. So basically it enhances the "blackground" and/or noise floor of your music.
The foam does this by absorbing sound waves.
I honestly think you would get a bigger tweak with a room full of this treatment than with rocks, and it is perfect for the 'perfectionist' as it comes in many thicknesses, colors, sizes, shapes,....
*edit: oops, didn't realize you were located in Sweden, lol