Germany's Auto Motor und Sport calls it an "ingenious trick", explaining that designers for the great British team have used the rear suspension to mimic the now-banned wing profiles beneath the main wing.
"It will be interesting to see if Charlie Whiting is responsive," the report said.
"If he does not object, the competition will have to catch up quickly."
A report on F1's official website said the McLaren solution "is considered legal by the FIA", but rival teams are likely to protest loudly.
That is because of how difficult a complete re-design of entire rear suspension layouts would prove.
It seems the likes of James Allison and Adrian Newey, perhaps the most respected technical brains in F1, were caught by surprise.
"All I've seen are some blurry pictures," Ferrari's Allison said, "but I would like to know more about it because it does interest me."
Red Bull's Newey seemed to doubt the legality of McLaren's solution.
"I have not seen the photos," he said, "but as it is described, it sounds as though there are eight suspension elements, where only six are allowed.
"Moreover, there are clear rules for the width of the suspension."
Auto Motor und Sport said the FIA gave the McLaren "the green light" last summer.
Suspension aside, Jenson Button sounded confident the Woking based team is set for a much better season, after the podium-less calamity of 2013.
"The basic car itself is where we want it to be," said the 2009 world champion.
Button is less happy with his own condition, having sat out the last three weeks of his usually intense physical training with a knee infection.
"I'm not as light as I will be at the first race, but I'm definitely going to lose another kilo by race one," he said.
Button was also upbeat about F1's new era, saying the torque of the V6 engine made it feel almost as powerful as the awesome V10s of last decade.
"I imagine that by the end of the year, we will not be much slower than at the end of 2013. Maybe two seconds," he said.
Unlike the troubled Renault-powered teams including Red Bull, Ferrari is also enjoying a solid start to 2014, with Allison saying there is "no killer in the car!"
"It is important that we have made no fundamental errors," the Briton told Auto Motor und Sport. "At the moment we can do what we want to be doing."
Mercedes-powered Force India's Sergio Perez is slightly less impressed with his start to the season, saying the V6 engine is "difficult to drive".
"The cars have so little grip that it's almost a little scary," said the Mexican, "but everyone here is having problems.
"I assume it will be quite different in Bahrain," he added.