Mar.29 (GMM) Norbert Haug has the 'F-duct' debate around by admitting he questions the exhaust solution featured on this year's McLaren car.
Some teams - notably Red Bull, Lotus and Ferrari - have complained loudly about the W03's aerodynamic configuration, arguing the F-duct ban completely ruled out similar systems that are triggered by a driver's movement.
Mercedes argues that its new F-duct is entirely passive and is triggered not by the driver but by the activation of the 'DRS' rear wing system.
So far, the FIA agrees, but it has led to suggestions Mercedes is only performing in qualifying because of its questionable F-duct, before struggling in the race when DRS use is much more limited.
"We have to live with that," Mercedes' motor racing chief Haug is quoted by Sport Bild, "until we are faster in the race, but it's not true that we do not have a good car.
"We are a serious team that has to pretend nothing; we have prepared well in winter testing."
Team boss Ross Brawn said recently he suspects all the fuss about Mercedes' F-duct is a diversion when it comes to the exhaust solutions taken by some of his rivals in the wake of the blown diffuser clampdown.
Haug agrees that championship leader McLaren's solution, for example, is "probably not what they (the FIA) had in mind when the blown diffuser was banned".
But he also said Mercedes is not threatening to protest the "clever" British team.
"It is quite legitimate that we ask the FIA for a clarification, otherwise we could be missing a trick.
"It's part of the game," he explains.