That frequency looks to good to be true. or is it just me?

You can take my word that they are very good and sound quite flat... or you can try them for yourself, they don't cost all that much anyway.

I trust Fidue for making good iems but that frequency graph has almost literally no spikes... then the linearity is just insane if that's true. Compare the lows and the mids with the frequency graph of the Hifiman HE1000 and you'll realize something's gotta be off. This thing can't better than a $3000 headphone right?
But anyways, I do appreciate all Fidue iems like I have said.

Of course acoustic treatment of full sized headphones make a huge difference on dynamics and staging. You don't get this IEMs.

I have heard that IEM measurements are not that accurate in general especially in the high frequencies and I don't have much experience with fq measurements of iems unlike headphones so I guess it may be right after all.

All I can say is that they sound great! =D

That sums it up well!

Update: Updated cable specification

Great review of an excellent earphone.