I think the GT3 RS is as fast as the model that was tested in "autozeitung". I also think that the GT3 RS is faster than the Challlenge Stradale. If you extrapolate the measured times, the GT3 RS should be a whole lot quicker than the CS up to 200 km/h.
IMO the Challenge Stradale is beautiful and makes a wonderful noise. But also "auto, motor und sport" figured out, that it is not that much faster than the standard Modena (not talking about track times - waiting eagerly for the "Supertest" of "Sportauto").
Well, how should it be possible, with only 25 hp more and NOT that considerable weight reduction as promised by Ferrari...

regards
sr

PS: what the Modena really needs, is a bigger, far more powerful engine...