Mercedes' 2011 car is the shortest on the grid, according to Germany's Auto Motor und Sport.
Bild newspaper has therefore christened the W02 the 'mini Mercedes' after learning that the wheelbase is 9cm shorter than the Red Bull, 5 than the Ferrari and a whopping 27cm smaller than McLaren's MP4-26.
The silver car has been heavily upgraded for this week's Barcelona test and the looming start of the season, with Nico Rosberg admitting he has felt real progress.
Michael Schumacher drove the upgraded car on Thursday.
"We know the Red Bulls are very strong and they are the ones we need to look at," said the seven time world champion. "We are certainly not quite in this position, but I never expected to be at this stage.
"The season is long," Schumacher added, "and there is a big question mark as to who is coming behind Red Bull, and I hope we play a sufficient role in that."