07-11-12: Dhl93449All of the references that I have seen over the years that I consider to be credible, including among many others the ones I quoted and linked to earlier and Steve's comment above, are consistent with the conclusion that any benefits those kinds of tweaks might provide result from improvements in trackability, resulting in less noise being coupled from the servo mechanisms into other circuitry in the player. Not from a reduction in uncorrectable errors.
Well, if that were completely true, tweaks like Lightstop (green dye around outer edge) would have no impact on sound quality. But many have observed they do impact sound (including myself).
Best regards,
-- Al