Red Bull's chief technical officer Adrian Newey said that the "engine-dominated" changes that will be implemented next season would result in their success becoming depend on Renault's ability to produce the goods.
"The new regulations for the power unit are massively complicated," Newey told ESPNF1.
"For the engine manufacturers themselves, it's very complicated for us - the chassis manufacturers - and it's a very complicated installation which the mechanics won't take an instant liking to, probably."
Red Bull will go in search of their fifth consecutive World Championship crown, which would be a great accomplishment when considering that new regulations will see F1 teams revert from using 2.4-litre V8 engines to 1.6-litre turbocharged V6 engines.
"Certainly the regulation changes are engine-dominated," said Newey.
"It's not at all clear at the moment whether one of the three manufacturers (Renault, Ferrari and Mercedes) we have next year come up with a better product than the other two from both a performance point of view and also reliability, which could be quite a concern at the start of the season, certainly.
Newey added that this significant change in output is not their only concern.
"So it's very hard to judge where we'll be at the start of the year. We've also got some quite significant aerodynamic regulation changes which are not nearly as big as the ones we had in 2009 but still by normal year-to-year standards very big changes."
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