Before starting the review I'd like to explain a few thing about myself so you can contextualize my advice/review.
 
I'm a 24 years old student in IT, my passion in life is Sound Design, I also like the mixing / mastering phase of electronic record. I don't play any instrument since I can't due to an accident that cut my tendons and ligaments on one of my hands.
 
I listen almost exclusively to electronic music mostly to :
- Deep House / Classic House (ex: Ten Walls / EDX)
- Glitch Hop / Neuro Hop (ex: Kursa)
- Experimental (ex: Autechre)
- Techno (ex: Paula Temple)
- Hardstyle (ex: Warface)
- Electro Pop / Future Whatever (ex: Odesza / Cashmere Cat)
 
 
At first I was on the market for a pair of portable headphone in the 500 $ range but I couldn't find any really flat headphone in this price range that had all the thing I "needed" (non proprietary cable, detachable cable, good comfort, fold able, etc.)
Then I decided to look on the IEM market and after a few days ( a lot of hours ) comparing the measurement available on Innerfidelity I found what I was searching for in term of frequency response. Something as flat as possible in the Sub/Bass/Mid-Bass/Mid region with a good extension in the highs and a gentle roll-of to avoid fatigue.
This was the SD-2. ,
So I decided to give a try to IEM because I never even consider these as an option to listen to music, so this is my very first pair of IEM, reason why you should read and interpret my review in this context.
 
I then decided to order the SD-2 from Thomann, received them and I wasn't able to wear them because they were too big for me, so well I had to sent them back and I then ordered the SD-2S which at the beginning seemed way too big, but with "retreat" ( don't know how to say this in English but when you think to something a few times after, you have a better view of it...) they are not too big but there's something that doesn't feel right, even after one month wearing them.
So obviously, why do I kept them ? (Read below and you'll know)
 
 
The Sound Quality
 
 
They are super neutral, listening to music that has been correctly designed / mixed / masterised is an eargasm to me.
On the other side, listening to poorly masterised / mixed track, like almost 75 % of Hardstyle / Hardcore track is just horrible, the bass isn't there, highs are uncomfortable because of the ##### loudness war.
Well, these are, in my point of view the best friend of mixing / mastering engineer in that price range in term of frequency response.
The only thing that I won't do with these is maybe sibilant check since they are relaxed in the highs, but still with a great extension, but well a pair of DT880PRO/HD800 would be better for that purpose.
 
Then, the stereo image seems nice to me but since it's my first pair of IEM I won't go too far on that route because my perception of how a pair of IEM can compete with a pair of studio monitor isn't sharp at all.
I won't go into further analysis, because I won't call myself and audiophile, but more a nerd who lives for electronic music, but still a tech guys.
 
To make it short:
PROS
- These are Neutral, I hear some sounds in a way I've never on my Focal Studio Monitor / Beyer DT880PRO
- These are Clean, if you hear some rumble in the Bass, of something that doesn't feel right, then you can be sure that this is related to the record not to the IEM and I think that as Mixing / Mastering Engineer this is one of the most important point, be able to have confidence in the support you're working on.
- These are Neutral, (Yes, again), so if you're accustomed to IEM/Heaphone that got a, even slight, boost in the low end you'll find these light in the bass, but at a correct volume to me the relation between frequencies between 20 & 2000 Hz is just so close to perfection that saying something on this would be snob-ism
- Stereo Imaging is respected and it's not over-made
 
CONS
- These are slightly slow, on some fast type of music the bass can feel a bit slow, Hardcore  ~180 BPM suffer slightly from this but honestly, it's really really slight and it's also often related to the records themselves.
If some other owner didn't speak about this I wouldn't even have compare with my other gear this particular point and I honestly think that I wouldn't have noticed this since this isn't a critical point for me.
 
The Build Quality
 
PROS
German Quality. Period.
 
CONS
The ear guide on the cable doesn't seem to be removable. I don't like ear guide... Is it really a cons ? ...
 
Fit, Comfort
 
PRO
The fit is, in my case ultra secure, there's no way that (even without the ear guide) they could fall. You can take a convertible car on the highway with these.
 
CONS
In my case they aren't comfortable, I don't know if this is because IEM are not comfortable for me since it's my first pair of IEM.
I use the xS tips, I've tried the Small from Comply, they are way way too big for me so I'll stick with the xS from InEar.
The 30 first minutes are okay, after 45 it become uncomfortable, after 90-120 minutes painful in the upper concha.
I have them for around 3 weeks now so I still have to get used so this review is non definitive.
I would say, if the comfort is the important-est point for you, read the other reviews because my point of view might be biased by too high expectation from a "Universal 2 Custom" IEM pair or simply because I never wore IEM for more than 5 minutes before these.
 
The Word of the End 
 
Listening to music and working (mix/mastering/sound design) with this product is a real pleasure, my best experience so far in term of neutrality,  I might even get a pair of the Customs one day if I have the money.
I wouldn't exchange these for anything even if I have some fit / comfort issue.
I highly recommend these to anyone that wants a neutral and natural experience, either for pleasure where they'll shine with their natural sound and relaxed highs or for work where their neutrality will help in mixing and mastering.
A big Thumbs Up for InEar, nice and helpful guys by the way.
 
EDITED : Typo, Poor English Level, Etc.