After a bunch of experiments over the first races of the campaign, the team thinks it finally has a direction it needs to pursue in a bid to deliver a package that is both quick in high-speed corners but then not sacrificing performance in the slow sections too.
Team boss Toto Wolff has called recent months a "painful learning curve", but senses that things are on the up as he says the factory is now flat out in preparing a run of developments that it hopes can move it closer to the front of the grid.
"The design office is all in, and the production and operations are flat out," he said. "The race team has been doing a good job, so all of the factories are really in sixth gear in order to bring stuff to the car that we believe can be very helpful."
The bulk of the changes for Miami were made out of view, as the shape of the underfloor's roof was reconfigured to increase local load at the front of the assembly and alter flow distribution to the rear section and diffuser.
These changes might not be visible but it is clear how they have had an impact on the edge wing's design, as the forward section is now cranked more aggressively and features five strakes along its length, rather than two.
The strakes also have more definition than their predecessors, as they are creating more of a horseshoe profile that edges away from the trailing edge, rather than terminating on it.
In addition to the floor changes, Mercedes also had a couple of track-specific items available in Miami. This included a front wing flap option with a shorter chord to help balance the car front-to-rear (new specification top, left image, red arrows show how much the upper flap has been trimmed).
Meanwhile, to aid in cooling the power unit and ancillaries, the team also ran a revised cooling layout on the W15, with the engine cover's louvered panel exchanged for a solution with enlarged and more louvres (top, right image).
Red Bull goes for weight-saving
In terms of its noted updates, Red Bull made a very small detail change to its edge wing for the Miami Grand Prix, with one of the support brackets removed in order to save weight, given the remaining brackets are able to offer enough support under load.
And, while it has not been busy on the update front it is interesting to take stock of how it has been managing its cooling configuration since the start of the season, especially given how different its layout is to the rest of the field.
The team made a change to the size of its horizontal 'shark mouth' sidepod inlet in Japan, reducing its height.
This also led to the introduction of the additional snorkel inlet beside the cockpit (see the ROKT sponsorship logo for reference).
And, while the four louvre outlet panels on the side of the engine cover were no longer present at that race, it has since returned for China and Miami, as the team has required more cooling capacity.
There have also been a series of changes made to the cooling outlets housed within the channels atop the engine cover shelf, with a three-louvre solution used in Japan (inset, left), whilst a more rearward but cavernous option was employed in Japan (inset, right).
These solutions were combined for Miami though, as a two louvre panel was fitted ahead of the more cavernous outlets.
