Front exhausts still possible for McLaren, Mercedes
But leading figures of the Woking based team did not rule out the appearance of the innovation on the MP4-26 at some point between now and the start of the 2011 season.
Indeed, closer inspection of the car on display in the cold Berlin air on Friday showed some of the detail beneath the bodywork had been molded in dummy plastic.
Engineering director Tim Goss admitted: "It won't come as any real surprise or shock that the exhaust solution that you see on the car today is not what we intend to be testing or racing."
He flagged some "novel solutions" to appear before Bahrain not only on the new McLaren but also the racers fielded by the team's competitors.
"Be warned, you haven't seen it all," boss Martin Whitmarsh advised reporters in the German capital.
He said certain "bits and pieces" of the MP4-26's eventual race specification have been "hidden from you and our competitors" for the launch.
There has also been speculation that Mercedes' new W02 car will eventually feature the Renault-like exhaust exits near the sidepods.
"Before we get to Bahrain you'll probably see a number of teams with different solutions to get the benefit from the exhaust energy," admitted team boss Ross Brawn this week at the Valencia test.
"I saw Ferrari have some different options," the Mercedes chief added.