Mercedes needs to have more of its drivers at the front of the DTM field in 2016, even though Pascal Wehrlein ended its title drought this year, Gary Paffett believes.
Wehrlein became the first Mercedes pilot since Paul di Resta in 2010 to win the DTM title, but was one of only two drivers to take a race win for the brand, along with Robert Wickens.
Audi and BMW had six and five race winners respectively, and the next-best Mercedes driver in the standings after Wehrlein was di Resta in eighth.
Mercedes is also without a manufacturers' title since 2010, having finished third in 2015 as BMW prevailed with what Paffett dubbed "the worst car this year", aided by the series' performance weights.
Paffett believes Mercedes' off-season focus should be on helping more drivers get "peak performance" out of what will be a new C-Coupe in 2016.
"A lot of the time there was one or maybe two Mercedes that were quick but within a lot of Audis," Paffett told Autosport.
"If we could get the best out of the car, we could fight at the front.
"But it was more difficult to do that than the other guys and that's what we need to work on in the winter, to get more of the cars to the peak performance.
"That's where we struggled this year, whereas for Audi it seemed to come more easily, to get more of their cars at the top."
Two of Mercedes' three race wins came at the Norisring in June and Wehrlein claimed the other at Moscow Raceway in August.
Paffett feels the Audi was also getting more out of the series' control Hankook tyres in cooler conditions during the 2015 season.
"In the cold weather, the Mercedes doesn't really work the tyres enough and Audi seems to have an advantage there," the 2005 champion said.
"Where it's been cold we've struggled a bit, that's just down to us not getting them to work."