Nico Rosberg says he was able to feel the difference with each of Mercedes' experimental Formula 1 parts during the Barcelona test.
As it chases a third-straight year of domination, Mercedes focused on reliability during the first week, achieving what Lewis Hamilton felt were "crazy" mileage targets.
During their combined haul of 526 laps over the four days, Rosberg and Hamilton tried a host of new components in the quest to stay "innovative".
A new nose trialled on Thursday morning and a new floor on Wednesday headlined the list, and Rosberg said each delivered a change in feeling.
"For sure, you can feel it," he said. "Small steps every time.
"The car is quick, I love the way it looks. There is some real innovation on there and I'm very impressed by that.
"I think it's cool how you can really see how far we have come as a team. If you look five years ago, we weren't able to make such innovation.
"But now there are so many different things that are just ahead of the game.
"Not saying we are definitely the quickest, but there is some good stuff on the car, which is impressive."
Mercedes elected not to use anything softer than Pirelli's medium-compound tyre during the four days, as Ferrari topped three of the four sessions, including two with the new ultra-soft.
Rosberg said Mercedes has a "good picture" or where it sits, despite not showing its hand.
"I've been paying attention of course," he said.
"We have strategists and they are doing all of the calculations already, so more or less we know where we are.
"They are able to see fuel tanks, low tanks, after a while they get a picture of where everybody is.
"That's quite fascinating to see that work. We have a good picture."