I have used my EP51 in the gym twice so far, but don't really feel like the wings do much. Also, the eartips and wings are just 1 part, as seen in the picture below. Can't find the size of the nozzle, only that the speaker size is 8.6mm. I could maybe measure it when I get home. I wonder if there even are regular tips with a bore that wide, and if it would be possible to get a comfortable fit because the Meizu supplied tips are angled instead of straightDon't have the EP51 so unfortunately I can't compare the sound between the 2.
Sound is typical v-shape with boosted sub-bass (basshead level). There's a bit of bloat and veiled sound.
However, simply replacing the stock nozzle screens with "regular" $0.10 stainless nozzle screens lowers the boosted bass, gets rid of the bass bloat, clears up the veiled sound, and adds clarity. I talk about it in more detail in the comments of the EP52 review.
As far as the eartips, they're your standard generic silicone tips. It's a 2-piece setup - the shell has 3 different silicone 'covers' that incorporate an ear stabilizer wing. Then on the nozzle you insert totally standard silicone eartips. You could tip roll the ear tips with anything you want (that fits obviously) - KZ Starlines, Comply foams, double flange, xmas trees, Symbios, SpinFits, Spiral Dots, etc. I haven't measured the nozzle, but it looks to be your common 3mm-ish nozzle size.