Aguri certain of customer cars in 2008

Both teams are involved in arbitration with Spyker, who are claiming that Super Aguri and Toro Rosso are already using customer cars this season.

But with Prodrive's entry now in doubt as Williams threaten legal action if the team enters next season with customer McLarens, speculation has suggested that both Super Aguri and Toro Rosso could also get dragged into the row.

And if customer cars were outlawed for next season, both teams could be forced to change their plans for 2008.

Super Aguri managing director Daniel Audetto was adamant, however, that the team do not have any concerns about the Prodrive situation affecting his team.

His team intends to race next season with a 2008 Honda car, even though they may not get hold of the car until the start of the European season.

"Let's just wait and see," he told autosport.com. "We have some formal assurances that we will race customer cars next year and we are confident it will happen.

"We have no problem, we know that we can race - otherwise we don't race. There is nothing we can do."

When asked if the team would consider racing this year's car if customer car teams were not allowed, Audetto said: "We are not even considering it. We just have to wait and see.

"We had assurances that we can race customer cars next year and we are not the only ones. I am confident that the people who gave us this word will honour it. Important people assured us we could race with customer cars."

Toro Rosso team principal Franz Tost said his team's use of a car supplied by Red Bull Technology meant they did not classify themselves as a customer car team.

"We don't have a customer car," he said. "We are a constructor and therefore there is no concern about this."

Audetto added that he was surprised the customer car situation had suddenly become an issue, because he believed it has been clear since the FIA invited entries for 2008 that customer car teams would be allowed.

"It is a problem of the FIA rules," he said. "Otherwise tell me why they receive 22 entries to race from 2008 and they choose Prodrive?

"Many teams - in GP2, F3, and Formula Renault - never had in mind to be a real constructor with 500 people and a 500 million dollar budget."

F1 team principals are likely to discuss the issue of customer cars during a meeting at Interlagos on Saturday morning.

Williams have been vehement against customer car teams next year, saying these pose a threat to their own existence.

And they are adamant that customer cars are a commercial issue and not one for the FIA to resolve.

"The Concorde Agreement is an agreement in law, it covers commercial matters which the FIA have been told by the European Commission that they are not supposed to be involved with," Williams co-owner Patrick Head said earlier this month.

"They have been told they must not interfere in commercial matters.

"Obviously if a team comes into Formula One without any investment in the staffing and equipment that we've built up over the last 25 years and gains access to a (customer) car...then it's a serious commercial threat to us."