Formula One world champion Jenson Button will start next season with a more aggressively designed McLaren than the one Lewis Hamilton struggled with for much of this year.
"It's still too early to be able to say with any confidence how competitive we'll be," engineering director Paddy Lowe said in a Q&A provided by the Mercedes-powered team on Monday.
"All we can say with any certainty is that we've approached this (20010) car more aggressively than we perhaps have in the past."
Mercedes have taken over Brawn GP, who won both titles this year. Button has since moved from Brawn to McLaren, where he will partner 2008 world champion Hamilton.
"We've used the knowledge we gained from heavily developing (the) MP4-24 (car during the 2009 season) to stand us in good stead with the 25," Lowe added.
"We feel we're making very good progress, but, equally, we know there are some very capable teams out there too. I'd be surprised if Red Bull Racing and Ferrari don't come out with very strong packages and I think Mercedes GP will produce another extremely quick car."
McLaren managing director Jonathan Neale said the team were looking forward to the new pairing.
"We know that Jenson is fully capable of learning very quickly, taking things onboard and absorbing information fast," he said.
"In fact, we are looking forward to that hunger - it will be about how we prioritise his arrival in January to take best advantage of that desire to learn and improve."
Team principal Martin Whitmarsh said McLaren, who have not won a constructors' title since 1998 and finished third overall this year, were well-equipped to manage the pair.
"We feel confident that, as an organisation, we'll be able to manage the demands and expectations of our drivers," he said.
"Lewis and Jenson are both world champions, they know what it takes to win, and I'm sure they'll both be very motivated to push each other to deliver even greater results.
"It's my job to positively harness that competitiveness for the greater benefit of the team."