Although there are obvious advantages in upgrading for a power track like Montreal, the final choice will be influenced by the fact that some drivers have used different numbers of elements.

Even those who have only used one set thus far have run different total mileages, for example due to first-lap incidents.

Two Renault-powered drivers are on the cusp of grid penalties, including Monaco GP winner Daniel Ricciardo, who took a complete set of second elements at the Chinese GP, following a failure in Bahrain.

The Australian suffered an MGU-K failure in Monaco and will be guaranteed a 10-place penalty as soon as he uses a third.

A third energy store and third control electronics will also add five places apiece.

McLaren's Stoffel Vandoorne is also on the bubble, having used two control electronics, and he'll get a penalty if he takes a third.

Of the other Renault users, Carlos Sainz and Nico Hulkenberg have used two MGU-Hs, and Fernando Alonso two turbos, but with those particular elements penalties won't kick in until they take a fourth.

"We've a new spec engine," Renault Sport F1 boss Cyril Abiteboul told Motorsport.com.

"We have yet to confirm the introduction, because the mileage is not the same across all cars, so we will see where and when exactly we will introduce that new spec.

"I think we have six engines available, subject to the last event on procurement in the supply chain.

"That's the plan, but not sure it's actually the best to introduce it in all six cars, in particular Red Bull. We need to look into that. We always work in partnership with teams, trying to do the best for the overall season result.

"It's a small gain in power, although we know we won't be the only one. It's mainly in the ICE that we can expect more power. This has to be the focus, and it will be the focus for all of this year, and maybe next year."

Red Bull boss Christian Horner suggested that any improvement from Renault is welcome.

"We're hoping for a reliable MGU-K," he said. "There is a small upgrade coming for Montreal – every bit we need at the moment, so that's hugely important for us."