I am still reacting to various answers.
Although it is a matter of taste, I find that if you want to adapt to your taste the alTerr Solaris Urbino, it is so easy. I started from 0 ... I speak only French, and I have little knowledge in English, and yet I successfully managed to modded my Solaris Urbino 18m at my ease, make it more French.
I understand quite well, it takes motivation, and sometimes it's hard to have one, but at one point, we will be lost with all these paying addons including models already existing in freeware ...
I saw that Perotinus says that the 3gen addon does not satisfy him, well I agree with him, too. In France, we have a lot of C2, and it is true that we are expecting one on Omsi with a quality close to alTerr, or Chrizzly, or even that of the creator of Bremen who does an excellent job.
Thomas U. talks about SETRA. I am surprised that at present there is no "modern" SETRA. We always stay in these creations of "old buses". S415NF, S415UL, S416LE etc ... It's a shame to always see the same models whether in payware or freeware, I no longer feel this urge to play Omsi.
Rest assured, I am completely grateful to the 3D model of the Solaris Bremen, it is simply beautiful, good continuation to you.