Before the Monaco Grand Prix, weekend Honda announced it would return to F1 as a fully-fledged engine manufacturer by supplying works power units to Aston Martin from 2026, when F1 moves to new engine regulations with a higher degree of electrification and sustainable fuels.
Honda is the last of the six manufacturers that registered for the new engine cycle to commit to a programme, which leaves McLaren, Williams, Haas and AlphaTauri without bespoke deals.
As Red Bull's secondary team, AlphaTauri will benefit from its parent squad's Ford tie-up, while Haas is inextricably linked with Ferrari through its technical partnership with Maranello.
That leaves Williams as one of the teams destined to remain a customer for the time being, with new team boss James Vowles exploring whether to remain with Mercedes or find a deal elsewhere.
Vowles acknowledged the first year of the new engine cycle "potentially becomes a little bit difficult" for customer teams to integrate the new power units into their chassis, but he believe customers can still be competitive if the regulations remain stable.
"I think the first get go into 2026, potentially there it becomes a little bit difficult," Vowles said. "But the learning will kick in shortly after that.
"I think what Aston has shown you is that you can take that and you can run with it, albeit Aston are going their own way. But I don't think it limits you necessarily in a stable set of regulations."
Vowles experienced both scenarios after coming over from Mercedes, which stole a march on the entire field in 2014 with its Brixworth-built engines the envy of the paddock in the turbo-hybrid era's early years.
He admitted there are obvious compromises for customer teams, but F1's stipulation to provide equal engines has allowed squads such as Aston Martin to be competitive, with Aston and Williams currently also taking Mercedes gearboxes to improve the engine integration.
Aston's split from Mercedes will coincide with setting up its own gearbox programme, a decision that Williams is yet to make.
Source: Autosport