I recently installed an Audiocom DVC-1 Master Clock and separate DVC-1 Power Supply in my Pioneer DV-525. Both items were closeout priced at Reference Audio Mods for $100 each. Luckily, specific instructions for the mod were available for the DV-525, as installation requires removal of tiny surface mount resistors and the old clock and trimmer. Once these items are removed you are pretty much committed, since replacing them is not going to be easy. I am no EE, but I was able finish the upgrade in about three hours by paying close attention to the instructions.
I had previously been using a Monarchy DIP feeding a ModWright massaged Link III. The new clock was better in all respects- much, much less of the awful digital glare. Inspired, I ordered a fistful of Black Gate capacitors and replaced all the stock ones on the DVC-1 power supply and noticed further gains in smoothness. Completely convinced, I sold the DIP.
*On a side note, I want to heartily recommend the glass (not plastic) toslink cable from a company called Sound Professionals. This low cost ($58-1.5m) cable sounds fantastic and has really surprised me at the potential of the optical interface. Better than coax (for me) even with the Bybee filter on the Link DAC's input.