On mine:
- highs much more extended and there are much more sparkle than the somewhat dark-ish original
- since the high-mids are brought out more than the original, the vocals has quite a bit more presence
- bass is less prominent and enveloping, but MUCH more detailed especially in the deep bass range, and extended down low in a rather linear manner without mid-bass hump or sharp roll-off. Some may find it less engaging than the original, think that's the biggest reason why suyama & co suggests people to try before upgrading, and would not offer the upgrade to areas where there's no place offering the SR for trial
- to me soundstage is more or less the same - spectacular as the original
- overall, it becomes the MOST realistic sounding and believable headphone/earphone/iem/ciem I have ever tried or owned. It's not dry or clinical, it's full of juiciness, but it's response is so even and well-tweaked that every instrument (vocal included) sound exactly like how it sounds in real life. (even among top tier iems, that is something few or none could achieve. good sounding doesn't necessarily translate into realism)
- and a very clean sound too - that's also very rare.
- in comparison, the original is something people would describe more as "musical" or "fun" sounding. Also vastly detailed, but the FR is more tweaked and flavoured than the SR. The original gotta be among the most engaging iem out there with its big and impactful bass.