While this doesn't bear directly on your question, I had Dan Wright of ModWright do his level 2 standalone and transport mods put in a SuperClock and ByBee filters on my Pioneer 38A (which is in about the same price range) and the improvement was immense. I would say the improvement upgrading from the 525 I had previously to the unmodified Pioneer 38A was about a 10% improvement, while Dan's mods were an 100% improvement. You might want to look for feedback on the ModWright forum at www.HarmonicDiscord.com. He does a lot of work on Sonys.
Greg
Greg