Sauber rules out double DRS as too expensive

With the Mercedes design, which helps stall the front wing for improved balance and an extra speed boost in qualifying, having been given the all-clear by the FIA, rival teams have been working out if they need to add it to their own cars too.

But the relatively limited benefit - believed to be just a few tenths of a second per lap in qualifying - against the high costs of fitting internal piping means that only the big-money teams are likely to pursue it fully.

Sauber chief designer Matt Morris said early analysis by his own outfit had left it feeling that it would be better off devoting resources to finding more normal development progress.

"We have done some evaluation on it in the factory, but at the moment it's not really working for us in terms of cost versus performance," Morris told AUTOSPORT.

"It doesn't really stack up for us at the moment. And beyond the cost versus performance issue, it's difficult to know exactly the potential benefits and then it's only really useful in qualifying as well.

"It's definitely a few tenths of a second in qualifying, but to get that [benefit] so many parts in the car would have to be changed. That's the problem."

Sauber ran with external piping on its C31 during testing at Mugello on Thursday, which prompted speculation that it could have been evaluating the double DRS further.

However, Morris clarified that it was simply measuring aerodynamic forces at the rear of the car.

"We have been running some pressure tappings around the rear, that's what all the pipes were," he said. "It's just pressure measurement, that's all."