I really dislike these discussions.
However, I do want to mention that I compared the performance of my then upgraded Onkyo PR-SC885 Pre/Pro with a stock unit in May of 2009. As to the sound, there is no question that the 2 units did sound quite different. The upgraded Onkyo 885 trumped the stock unit in all areas including being more open sounding with better more controlled bass, better imaging, better soundstage, clarity, dynamics (both micro and macro), and much more natural and relaxed performance.
Additionally, I have compared the early upgrade of this unit versus some very expensive Preamps and thought that upgraded Onkyo sounded superior.
Since my comparisons in 2009 my Onkyo PR-SC885 Pre/Pro has gone through many additional upgrades to the unit so that it's performance far exceeds what I heard in 2009.
I have also noted improved audio and I also believe improved video performance of my upgraded NuForce Edition Oppo 83SE Blu-ray player particularly after the latest installation of the Upgrade Company's proprietary shielding.