Ken: Check the AA Hi-Rez forums. The modifiers I know of are Stan Warren, Richard Kern, Dan Wright and Allen (?) Wright (one of the Wrights is a tube mod), and I'm sure there are others. There are various levels of mods and improvements from each of them, depending on how much you want to spend--I think Stan Warren's start in at a couple of hundred, and Kern's full monty can run $2500-3000 or so. My mod was done by Jerry Ozment of Audio Logic, who doesn't do them anymore, but after my latest transformer upgrade from him I'd say I have yet to hear any commercially available unit that sounds better than my 777ES on redbook, and SACD is absolutely stunning, easily better than the Accuphase and dCS SACD playback I've heard at my dealer (bear in mind I'm a big fan of the Audio Logic); I know people who have had the Kern upgrades feel the same way about their players.
This reminds me a lot of the early days of CD players, when various folks like Scott Nixon, Mod Squad, Musical Concepts and the like would modify and greatly improve stock Magnavox players, often doing their own brands based on the stock chasis (Magnavoxes were easy to work on because they had a lot of empty space inside them). Remember, everything available commercially is built to a price point, and therefore can be improved on; this is particularly true with the Sony players and players from other mass-market manufacturers. Nothing particularly wrong with them in stock form, but they can really shine with a good person upgrading the right parts in the signal path and power supplies. Elizabeth is absolutely correct about the warranties, though, and that is not a small consideration.
