Mine landed yesterday. The box says FMJ i8, but the label on the IEMs says I-INTO i8. Out of the box, I could sometimes hear the sub-bass dragons that live in these cans. They're mean. Vertigo inducing level of mean. But I couldn't get them to come out and play. No seal with stock tips. Great seal with my favorite wide bore soft silicone tips, but results in pretty massive and annoying driver flex due to pressure/vacuum, and sound stage is tighter too. Is there no port on these thing? I couldn't see any. Tips rolling struggle continued for almost a day now. Finally came up with a hack that allow me to use a firm narrow bore silicone tip and achieve very good seal.
I estimated about 80% of the dragons came out and party, and that's fine by me, not sure I'd like all of them out at the same time
Still got some driver flex. Waiting for KZ tips to come in, hopefully they'll work better. Back to my impression of the sound - sub bass is strong, but I feel mid bass lacks punch. Drum kicks don't sound as exciting as on my Uiisii E6. Mid remains very clear and sounds pretty much the same with any kind of tips. Upper mid is quite forward, giving vocals some biting and great clarity. Treble is recessed indeed, but not too bad. My Uiisii E6 has more sparkle, more mid bass, but less mid overall. Vocals sound fuller and more forward on the i8, but I like E6 better for instruments. Sound stage on both is very spacious.
All in all, the i8 is great. I'll need to find better tips for it. With better seal this might become my favorite IEM. For now, Uiisii E6 still hogs ear time.