The FIA announced this week its outline plans for the 2026 regulations, as well as images of what the next-generation challengers could look like, and teams have expressed some concern about the details of what is being worked on.
Motorsport.com revealed earlier that team bosses plan to bring up their concerns over the 2026 rules in Saturday's semi-regular meeting that is held with F1 CEO Stefano Domenicali.
One of the major talking points is how slow the cars appear to be performing based on the draft regulations that have been sent to teams, with plans to cut downforce by 30% and drag by 55%.
Early simulation running of 2026 models has shown they could be several seconds slower than the current F1 cars and barely faster than F2 unless tweaks are made to improve them.
Speaking about the speed profile of the 2026 cars, Stella said: "Well, I would say that at the moment, for the way cars are in the draft version of the regulations…the cars are not fast enough in the corners and too fast on the straights. These two aspects need to be rebalanced."
Williams team boss James Vowles backed up Stella's belief that the performance issue had to be addressed and said it was essential F1 maintained its place as the fastest single-seater category in the world above Super Formula and IndyCar.
"It's imperative that we are still the leading series in motorsport," said Vowles. "That's how I see us, we are the pinnacle of this.
"Therefore, as a result of that, we need to make sure that we're maintaining performance and the speed we have - and right now, there's a mismatch there.
"Fundamentally, the performance difference between an F2 car could be as small as a few seconds, and that's starting to get a little bit tight, especially when you compare it to other series around the world that you've nominated.
"But also these are draft regulations and just this week, in fact, there were two changes which took quite a bit of downforce away. I'm confident we'll get to a better solution in that regard. It's not that we're so far away, it's just a little bit more work is required."
Stella added that, from McLaren's perspective, the team backed the intent of the new rules for 2026, but improvements were needed from the draft proposals.
"We support the intent of the objectives at a high level," he explained. "However, if we look at the regulations in the draft form that has been circulated, they are still far from being able to achieve those agreeable objectives and intent.
"It is the time for the FIA, F1 and the teams to work together, listen to one another and contribute to form a solution that will allow the sport to meet those objectives.
"I think if we meet those objectives, we're going to have F1 in a good shape. But we need to make sure that, when it's the time of implementation, we actually deliver a product that meets those targets and objectives."
