In reality, it's nothing new, seeing as Marquez already used it at the Red Bull Ring, but we missed it and so we're only letting you see it now.
We're talking about his new front fairing, with the addition of a different air vent, which the championship leader is already using on both his RC213-V bikes, while his team-mate, Dani Pedrosa, still has the old aerodynamics.
The most obvious things it the difference in air-scope. While the air vent on Dani's bike is oval, Marc's is trapezoid-shaped, but we can also hypothesise about internal differences regarding the inner shape of duct and relative air box, so important in maintaining constant internal pressure several tenths of a bar higher than the atmospheric pressure.
Without being to make a detailed comparison, it's difficult to judge other aspects, but the fairing seems slightly less rounded, probably in an attempt to find a downforce able to better keep the front of the bike on the ground in acceleration. Contrary to the Ducati, in fact, the Honda's spoilers are very small, and totally absent on Pedrosa's bike and the Red Bull Ring taught us that keeping the front on the ground has an undeniably positive effect in acceleration.
With wings being banned as of next year, we await further research in this area, also with regarding to fairing shapes.
The Dorna decree is a real pity and denies us interesting solutions, actions that will be produced also on production (sports) bikes, as has been happening for years in the auto world, with front sections increasingly influenced by the wind.
We look forward to more updates on Monday, when many of the MotoGPs will takes to the Brno track in their 2017 configuration.