Firstly, where can i find Zen or Serenade? And do I message them to know or I can see somewhere what they sell?
Second, no, i was getting my groupset from probikeshop, i was now looking at used ones because that can make it cheaper, what parts can i rely on the chinese side, not just for lighter, but that can do the same as a shimano 105 or the groupset oficial that i am picking?
Thirdly, do you enjoy your saddle? is it confortable? I might get that if so
Forth, I will look for headset bearings, what measures should i considerate? I will buy some titanium screws at side thank you for the suggestion
First:
You can check the threads on this forum (under Road Bike Frames, Wheels & Components) where you will find more information on their offerings and how to contact them. There are also other threads for other manufacturers. You can go really deep and optimize price / performance, if you really want to.
Second:
I don't have experience with them, but people around here are quite happy with ordering Shimano parts from Anrancee:
https://www.aliexpress.com/store/1954042 (if you will consider buying from AliExpress). I am not sure about additional taxes to EU though, best you search this forum or ask the store directly.
I personally went with the CRUZBIKE carbon crankset from AliExpress and it has been ok so far (I have only used it on the trainer though). There are also some other popular and cheap Chinese brands like Leese or BigRock. You don't have to go with the carbon crankset though, as this is one of my personal priorities since I am a little bit of a weight weenie.
Third:
I am very happy with it. As far as objective characteristics go, it is well made, the top material is not slippery, and the padding is fair. Again, I have no idea, if the 3D printed version is as good. I think I got used to all the saddles I had in the past (all were different shapes, and one of them without any padding), but this was the first time I didn't feel like I needed an adjustment period. That being said, I think by far the biggest part of the saddle comfort is your fit on the bike, so it might not be the most important choice whether you go with EVA padded, 3D printed, or raw carbon. The preferences are also very subjective, as everyone has different physiology and needs in this regard. If anything, I would say it is the safest to go with something similar you already know suits you, or perhaps experiment only slightly in this regard. There is a whole thread dedicated to saddles on this forum, if you will search for it.
Fourth:
It is best to ask LightCarbon about what kind of bearings they use in the first place. The frameset is not the cheapest, so maybe they already include something higher quality.