The problem lies in the choice of the crank for bbright system (cervelo r5).
This thread's title describes the conclusion I came to: Red GXP vs Rotor 3D+.
What I like and dislike:
Red Like:
the look;
potential of changing the appearance and shaving view g;
the match with the rest of the Red components (no big fuss);
cheaper than Rotor.
Red dislike:
extra weight, compared to BB30 version;
24mm spindle, not native to bbright, not fully taking advantage of bbright;
necessity of using extra adapters.
Rotor like:
bbright native, 30mm spindle, full utilisation of bbright system, no adapters;
the same weight as Red crank (gxp with adapters, chainrigs excluded);
some say "cervelo looking" crank (debatable);
look better (imo) with q rings, which I would like to give a try.
Rotor dislike:
I can live with the graphics, but if I change my mind....;
weight,
more expensive;
some say "cervelo looking" crank

Some figures (compact):
Red: crank arms 415g, oryginal chainrings 157g, bb 85g, adapters 39-50g, total 707g.
Rotor: crank 475g, q rings 154g, bb 85g = 714g.
In this configuration Red is much cheaper £284 vs £421.
Situation changes when you go for lighter chainrings. At this point price difference comes to £30 ish.
What is the stiffness and performance difference between these cranks?
Compatibility q rings with Red...?
Now I'am on Red coupled with Record crank, standard bb 68mm. And I'm very happy.