I think you can try the hisoundaudio crystals too. I dont know if you can get these from where you are but worth considering. Why not VSD3? it can do good too. In your budget too. Cant say about durability though on these two, The reason i suggested the S0 was because of its build quality, SQ is good but build is awesome. These are good but those cables are not like S0. If you can take care of the cable these are good. I think Vsd3 has a okay cable. Crystals are slightly thinner.
The way I do these things usually is to get the best product I can within my budget or a lilttle over it. This time however there seems to be no clear cut, no second toughts "best IEM under € 100". At least I have not come across one.