What was your first tweak?

The flat discs that were held on to the top of the cd with adhesive was probably my first tweek. They did improve clarity in the treble. Next came the reference bands that stretched on to the outer edge. They were good too, easier to use, and removeable. I would still be using them, but I got a Pioneer PD-S95 transport that clamps the disc, and makes their use redundant.

Green edge on CDs.
I used a common paint pen.. Not the 'audiophile approved' pen, so obviously my painting was for nought. As only 'audiophile approved' spending counts for anything.
Making cheap tweaks out of simple junk will not do...
The tweaks have to be made and approved by 'experts, and have to cost at minimum 100 times what they cost to make.. to be an genuine 'audiophile' tweak.

Headphones. None will bother me cuz I hear nothing.