While there may be a dramatic change to the aerodynamic regulations in 2017, teams are continuing to push forward with development in the final three races of the season.
Added to that development work, for Mexico several teams have made tweaks to aid cooling, given the track sits 2250 metres above sea level meaning the air is 20% thinner than at most races.
This impacts engine power, cooling and turbo speed, while the thin air also decreases downforce and drag created by the bodywork.
Ferrari follows Red Bull's lead
Ferrari introduced a host of aerodynamic updates in Malaysia and Japan and it has been working on refining them ever since, but while most of its rivals are focused on front wing developments, Ferrari is putting its efforts into the Y250 area of the car slightly further back.
This weekend, the Italian team updated the bat wing fitted under the raised chassis but it has switched from a Mercedes-style design run in recent races to a Red Bull-esque winglet.
The winglet is shaped to create a pair of vortices to push the airflow around the sides of the car.
Ferrari has followed McLaren and Sauber in switching to the Red Bull splitter-mounted format, the design of which is likely to create a positive type of lift around that area of the car.
The splitter is critical as it's the first part of the car to hit the ground and if it can be made to ride a bit higher at speed, the car can be set up with more rake (a lower front-end height and raised rear) for more downforce.
To prevent the teams running a flexible splitter, it must resist an FIA upwards deflection test but it's possible the upturned bat wing might produce enough load to offset the stiffness required for the FIA test and raise the splitter slightly at speed.
McLaren data-gathering for 2017
It appears McLaren is pushing hard to develop its technical understanding of the MP4-31 in the final few races before on-track running is banned until pre-season testing in February.
Jenson Button admitted "we started off doing a lot of work for next year's car, so FP1 wasn't really any use for this weekend".
In Friday practice in Mexico, the team completed runs with extra sensors focusing on the front wing and latter runs with flow-vis paint focused on the point where the nose flattens to join the monocoque.
This latter run is interesting as this appears to be a relatively insensitive area of the car and there are no rule changes to the external surfaces for 2017, although the nose will be longer.
Other runs had cameras fitted to the sidepods looking forward towards the front tyres.
Usually, this might be for tyre temperature data gathering, but current infrared tyre temperature cameras are much smaller and permanently run in free practice.
So McLaren could be running a high-resolution thermal camera or perhaps it is looking at the tyre shape, as the team did with a different camera format and bright lights shining on the rear tyres at Austin.
Toro Rosso and Williams tweak brake cooling
Toro Rosso has chosen to upgrade its brake cooling in Mexico, to combat the thinner air and heavy braking requirements of the circuit.
It continues to follow the scoopless brake duct design, whereby the brake cooling air is collected between the tyre and duct, rather than an exposed scoop.
This is a trickier design to get right but when working well, it offers a lower drag solution.
The usual inner vane shape has been stretched inwards to create more of a scoop between the duct and tyre, forcing more of the thin air into the brakes without resorting to a major redesign of the brake duct set-up.
Williams runs a similar design to Toro Rosso and has also made tweaks for this weekend by adding an extra scoop.
This is a contrasting modification compared to Toro Rosso as the outer duct remains the same but a flat scoop has been bonded to it.
This scoop then breaks into the complex ducting inside feeding the brakes with cool air.
Haas braking headaches
Haas has chosen to test a different brake supplier in Brazil in its quest to get to the bottom of the problems that have plagued its drivers of late.
The American team uses brakes and uprights from Ferrari as part of its technical partnership.
This means the upright shape, open-blown axle is the same as Ferrari, as is the Brembo brake caliper, brake material and brake-by-wire system.
One of the downsides of taking non-listed parts from a supplier is that the rules do not allow for assistance in setting up and running the system.
Haas can work with Brembo on the caliper and disc/pad material as any team can.
This has led to some material changes from Brembo but another failure at Austin has led to the team assessing a supply of the Carbone Industrie discs and pads, which it will try on one car next time out.
There is a slight difference between the brake material manufacturers, with different heat-up and bite characteristics.
Carbone Industrie is believed to have more consistent performance and it is this rather than brake performance that Haas is understood to be chasing.
The difference in mounting systems and expansion of the material that joins the disc to the axle means this is a reasonably arduous design and manufacturing challenge in such a short space of time.