Sorry, it took a bit longer to make the video. Had to move my test rig to the kitchen because there's a construction site across the street.
I tested three drives: Mitsumi 4x, Mitsumi 8x and DVS DSR-1600H (DVD).
https://drive.google.com/drive/folders/1iXk6q … 4yq?usp=sharing
Verdict: The Mitsumi 4x wins by a mile. It has a unique seeking noise that fits a retro PC, not quiet but also not bad. What makes it stand out is that it has virtually zero motor noise and vibration. You can barely tell that it's on unless it's seeking.
The Mitsumi 8x was horrible. The seeking is objectively quieter than the 4x, but it has an unpleasant pitch and every motion is accompanied by a loud motor noise. It also vibrates a lot for an 8x drive, and after it spun up, it keeps spinning and vibrating for a very long time even if not doing anything. It also feels cheaper than the 4x.
The DVS is speed-adjustable, I believe I had set it to 6x or 4x. It has the quietest seeking mechanism, but also sounds a bit... futuristic, not very fitting for a retro PC. It also had the quietest motor, but oddly, a ton of vibration. It doesn't really come across in the video, but it made the whole table vibrate. It's only going to be worse screwed into an older case so I can't recommend it, but I'll see if it performs any better at 1x or 2x. It's a great looking drive though, which was the reason why I got it.
After this test, I would rather not send you the Mitsumi 8x unless you insist, because it's just terrible and not even worth the shipping cost. The Mitsumi 4x is currently in my 486 PC so I can't part with it yet unless I find a replacement. The other Mitsumi 4x from the classifieds site would have been perfect, but it's been sold since. I'd say keep looking and I'll send you a message if I find something good.