Renault has confirmed that both Red Bull drivers will run the latest engine upgrade at Monza this weekend.

"Red Bull will use the C-Spec right from the free practices at Monza," confirmed Renault's engine technical director Remi Taffin, "because they are in a position to prioritise performance without having to worry about those behind them in the championship.

"For our part and McLaren, we will not be using this specification, because reliability and consistency are the essential assets to reach our end-of-season goals," he added.

"The C-Spec is an evolution of the current B-Spec engine," he continued. "It's significantly more powerful. Conversely, it's possibly not as reliable as the current generation, hence the different choices made by each team.

"Depending on fuel used, the power gain is in the order of 0.3s per lap in qualifying on a circuit like Monza, which is a substantial step forward."

However, a new, more reliable and lighter MGU-K being used by the Renault works team is not being used by its customer teams.

"Today only the Renault team uses this version," confirmed Taffin. "McLaren and Red Bull did not want to make the needed changes for its integration. They have opted to take and assume this clearly identified reliability risk.

"However, to respond to the demands expressed after the incident with Max Verstappen's car that saw him retire in Hungary, we have developed an evolution of the version used by our two customers to reinforce its sturdiness."

While Verstappen will take the C-Spec without penalty, not so teammate Daniel Ricciardo, who for the second successive season will head to Monza facing a grid penalty.

"I've done some of my best overtaking moves there and I plan on doing plenty more this week," said the Australian. "It's obviously not ideal but Monza is a power track and one that we haven't been hugely strong at in recent years. It does mean plenty of action and fun for me in the race though."

Last year, starting from 16th on the grid, Ricciardo finished fourth.

"It won't be boring if I have to do the same again this year," he said.