By Andrew Benson
Motorsport editor at Silverstone
New rules proposed to slow Formula One cars will increase costs rather than cut them, says McLaren boss Ron Dennis.
Dennis and Mercedes boss Norbert Haug are concerned by the changes
The F1 teams have reached broad agreement on changes to the cars for 2005, and there are also plans to reduce engine power and tyre grip.
But Dennis said: "Some of the changes that have been proposed are going to be horrendously expensive.
"And that is in an environment where much of the dialogue in the last few months has been about cost cutting."
The teams will receive a dossier from governing body the FIA next week, detailing the changes it wants to introduce in 2005 and 2006, as BBC Sport revealed on Friday.
For 2005, this will include aerodynamic changes to the cars, a requirement for engines to last two entire race weekends, and for one set of tyres to be used for qualifying and race.
The changes to the cars have been agreed by the teams, and tyre companies Michelin and Bridgestone are close to agreement on the tyre changes.
Two of the engine manufacturers, Honda and Mercedes, are still holding out against the changes to two-race engines.
BMW sporting director Mario Theissen said: "On the engine side we have an agreement on certain materials and design restrictions, which was agreed in June and was originally intended for 2008.
"We have gone through that and checked what we can offer for next year and for 2006.
"It looks like we can offer everything for 2006 and quite a lot for next year. This will be forwarded to the FIA early next week.
"To me there is a question mark over two-race engines. I fully support extending engine life and would even go beyond two races.
"But if we do it next year already I'm afraid not every manufacturer could follow it and as a consequence it might be discussed to change the format to a two-day weekend with free engines on Friday.
"If we do that, the benefit in terms of cost wouldn't really be there.
"It would make more sense to go for the materials and design restrictions for next year and then a really big step in terms of engine life for 2006."
BMW is alone in objecting to the change to 2.4-litre V8s for 2006.
Its reasoning, Theissen said, is that F1 cars might not then be sufficiently more powerful than those in the new second division GP2 series that is due to replace Formula 3000 next year.
It will use four-litre V8s, which Theissen said could give out as much as 650bhp, while a 2.4-litre F1 V8 would have about 700bhp.
He added that the current three-litre V10s would be more effective in terms of cutting costs because it was easier to make them last longer.
Dennis said: "There is a genuine desire to address the performance of the cars and reduce power. I think that is in the interests of F1.
"Most of the discussion is originating from the teams and there is an acceptance by the teams to adopt most of the things that are being currently considered.
"But the big issue is the cost implications of some of the proposals, which is deeply concerning for all the teams."