Formula 1 teams have played down the prospect of next season turning into a development arms race on exhaust layouts.
That comes despite Red Bull's recent dominant streak, which is believed to derive from its efforts to perfect its exhaust layout and rear bodywork.
Although Red Bull's leap forward has opened up the possibility of teams now getting locked into an expensive development push in this area - just as blown diffusers were so important in 2011 - rival outfits think that exhausts will only be a useful, not decisive, factor.
McLaren sporting director Sam Michael said: "I think they are starting to run out of puff now. There are gains to be had, but you are into the third order now - which is good in a way.
"The intention of the regulation change 12 months ago was for there to be some R&D with the regulation change, but then it was going to restrict you getting anywhere near the potential there was last year.
"It will be important to get it right over the winter, but across the teams all the solutions are quite similar now. They are all pretty close."
Mercedes team principal Ross Brawn believes that there is still room for those teams new to the current preferred Coanda-effect design to get more speed - while those outfits that have used it all season may find the returns are diminishing.
"Sauber and McLaren got into the technology first of all," said Brawn.
"I remember even Adrian [Newey] had a few races where they had it on and had it off, because they were not sure. But now they would not give it up because they have obviously developed it well.
"We have seen in the short time that we have had it, that it is opening up new avenues. Perhaps that is where we slipped a little bit in the second half, because until you get involved in it you don't know what the potential is.
"The more you get into it, the more it opens up new doors. So that is why it was important that we started on it this year.
"We are starting to see some new avenues that we wanted for next year's car - things we can only do with a new car that we want to do for next season."
He added: "I am not sure it is what was intended when we wrote the regulations, but that is the nature of F1. It is not quite as powerful as we had last year because the engine mapping is controlled, but it is still producing a benefit now.
"Hopefully we are on a steep learning curve.
"I think the development of a lot of cars over the last few months has been mainly relating to that area, which is why there has been such progress, so it has opened up.
"We are on our second iteration of the system now, and there are probably some further modifications before the end of the year and certainly a revamp of the system for next season."