McLaren's new exhaust and floor is a last-minute copy of the Red Bull layout, rather than a reversion to a truly conventional system.
That is the claim of Auto Motor und Sport, after team boss Martin Whitmarsh ordered the scrapping of the ultra-complex 'octopus' exhaust within days of the Melbourne season opener.
It was believed that McLaren's fall-back option was the very conventional one seen in Barcelona testing, but the German report said the new MP4-26 layout is in fact reminiscent of the one seen at the rear and underneath Red Bull's pace-setting RB7.
The news will raise hopes that McLaren can be significantly faster this weekend compared with the most recent pre-season test.
I decided that we should focus for the start of the season on a solution that will definitely work
"I decided that we should focus for the start of the season on a solution that will definitely work," Whitmarsh is quoted as saying.
"We are blowing the exhaust gases as closely as possible to the rear tyres," he added.
Jenson Button on Thursday said the latest news had given him some confidence.
"I like McLaren's aggressive development. But Red Bull and Ferrari will be faster than us here.
"If we can score a few points that would be a good start for us after all the difficulties of testing," said the 2009 world champion.