I have always hated the term "Mods" when it comes to this stuff. When you break it down, it's an upgrade from stock components.

Now that I have that out of the way, I'm with 2X6, I have seen a few players that benefited greatly from being upgraded. I should note however that most of the upgrades that I have seen have all for the most part been on the video side.

Now the bad part. The price most of these guy's charge for "Mods" is brutal to say the least.

I believe in better capacitors when it comes to CD players and of course DAC's but some of the stuff is pure smoke and mirrors.