Bike Models Explained
The Magnus is the best bike for sustained efforts, sprinting and where ultimate stiffness is a priority. Selene is very well suited to racing, training and long distance riding. Its performance is on par with high end carbon frames, at a somewhat higher weight.
Regarding choosing the build level, the main difference between the different levels of one brand (Shimano, SRAM or Campagnolo) is in the decreasing weights as the price goes up. With modern high quality group sets, shifting quality does not vary much from level to level.
In short, Velocite frames and bikes are all different and cannot be directly compared one against the other. It is up to you to decide which one would suit you best given the type of riding that you would like to do. Please also keep in mind the geometries of each frame to asses if you will be able to achieve a riding position that you are seeking.