If you must mod it Tube Research Lab is the place to go. If you like Sony you may want to check out the other Sony CD players they have modded. This way you can keep your existing Sony stock. The TRL Sony 595 has gotten a lot of notice and great reviews. This will set you back about $700 ($150 for the CD and $550 for the mods). By the way, all TRL mod packages are $550 and don't ask me what they do, I don't know and they won't tell, but there are some threads here that discuss TRL so you may want to check them out.
For what it is worth I don't have a TRL Sony, but they modified my Alesis Masterlink 9600 with great results.
For what it is worth I don't have a TRL Sony, but they modified my Alesis Masterlink 9600 with great results.