Furthermore, with the German car manufacturer having data from pre-season testing when it ran with its launch spec sidepods, the event will also be critical to understanding if it needs to change car concept.
Following a filming day run at Paul Ricard on Wednesday where the team revealed little about its Barcelona plans, the scope of what it is changing for this weekend was revealed on Thursday when George Russell's car arrived at the Barcelona track.
As Mercedes unloaded the W13 from its transporter at the Circuit de Barcelona-Catalunya, it immediately became obvious that the team had a few new tricks up its sleeve.
Looking closely at the images, Mercedes has followed the example set by Aston Martin, and which Ferrari and Red Bull have already acted on, by introducing its own 'bib wing' designs.
Sat between the bib and the underside of the chassis is this winglet (red arrow), which also appears to stretch out a little further.
The aerodynamicists are using these wings as a means of better managing the airflow in this region of the car.
The vortices shed by them are being used to manipulate the characteristics of the edge vortices shed by the bib below, which is narrower by regulation this year.
One of the big talking points of the W13 has been porpoising and the role that the design of its floor plays in the ill effects that ensue.
For Spain, the team has revised the design of the floor's edge, adding a scythe-like edge floor wing that's attached at three points along its length by metal stays.
The shape of the floor alongside the edge wing had also been altered in order to incorporate it, with a more pronounced raised section visible before it bleeds into the design of the floor spat region ahead of the rear tyre. This has also been altered and no longer appears to be as upswept.
The team is also still looking to reduce the weight of the car by any means necessary too, as whilst the livery tweaks made to the wheel deflectors and rear wing in Miami have been removed, the team has not returned the livery to its pre-Miami status.
It's not a huge weight saving but the removal of some of the paint will help it get closer to the minimum mass that they're allowed to run at.
