McLaren came away from Friday at the British Grand Prix pleased with a 'productive' day of running.
"It was definitely a positive day," Sainz said. "Especially with Lando's car, it was evaluating a lot of new parts that look like they're working well.
"Hopefully I can get them on Saturday and we can keep improving as a team because it was a positive Friday."
The track conditions were tricky for most drivers, with a mixture of factors including the wind and new track surface contributing to the on-track struggles.
"It was a combination of wind and track surface being very grippy but at the same time being snappy," Sainz commented. "So grippy on-line, not grippy off-line. That was a challenge and the cars definitely feel different to other circuits."
Norris confirmed that the new parts that he was running were "small bits here and there, nothing major" and that the team would spend Friday evening evaluating the data.
The Briton added that the team will feel more nervous after the final practice session on Saturday, as it has consistently placed inside the top ten on Fridays.
"We've had a tendency to be inside the top ten for a few Fridays in a row now, and when we get to Saturday we're a bit more nervous after FP3," Norris said.
"But it was a good day on the work side of things, not so much the pace. I think that's a nice bonus for us all but in terms of getting the car comfortable to drive in the long and short runs, we got some work to do still.
"It was still a reasonable day but it wasn't the cleanest. I made some mistakes here and there and cost a bit of track time altogether, but apart from that a productive day."