What’s your vote for the most ridiculous, overpriced, and useless tweak?

Geoffkait you Venn.

I’m not a tweak fanatic but...

Shakti Stones standing on edge on my tube amps between the mains and output transformers definitely makes an improvement in the lower frequency separation. It has the same effect as moving the transformers further apart (I have built many a tube amp and experimented with tranny placement and orientation as my reference).

Ansuz Mains cable, 23K.  Most likely some poor sucker will buy it.  

Back in the mid 90's, Michael Greene of Roomtunes fame, (sorry for any mis-spelling) made his bid to convince me that the kind of screws (re. what they were made of), that held the circuit boards in place, would make a dramatic difference in the component of which they were applied. I would assume he was trying to control the resonances to the circuit boards by said screws. While I have never been in the position to test his theory, I remain skeptically unconvinced that this would make any worthwhile improvement other than drive up the price of the component. IMO.