Toro Rosso team boss Franz Tost believes customer cars will not deliver as dramatic a cost saving to Formula 1 as some believe.
With F1's biggest teams currently evaluating a way for customer cars to work in the future if needed, Tost says he is sceptical about the overall benefits.
For although there is no doubt it would save smaller teams expenditure in terms of design and construction, there would still be a price to pay for purchasing a car from a big rival.
Speaking to Motorsport.com, Tost said: “It would for sure be a good way to start for a team coming in to F1, like was the case with Toro Rosso.
“Currently I have a little bit the feeling that people underestimate the costs for a customer team because it is not as cheap as they all think.
“If you want to be a competitive customer team then you will need to buy from a top team. And they will be working at a high level, not just from the technical side but also from the financial side.
"It will be quite expensive; it will not be for nothing.”
Around half of the top teams' budget
With costs so high at the moment, Tost does not believe that a customer outfit would be able to operate at much less than half the budget of the big teams.
“On one side it will be cheaper because you don't have complete costs for R&D, for wind tunnels and all this kind of stuff,” he said.
“But you have to build the parts, and this costs money.
"I think it would be around 40-50 percent of the [top teams'] budget.”
Interview by Oleg Karpov