Winterbottom recorded 13 top 10 finishes and finished 10th overall, just 20 points adrift of ninth-placed Pye.
With eighth to 13th overall covered by just 161 points, the Team 18 executed their seasons brilliantly to seal top 10 finishes.
However, ahead of his team's sixth season as a standalone squad, Schwerkolt has eyes on greater successes in 2021, with race wins the next marker.
"2020 was a year where Team 18 stood up with multiple podiums in our first-year as a two-car squad, so for 2021 we want to take the next step forward and be a consistent force in the Supercars championship," Schwerkolt said amid the reveal of Winterbottom's 2021 scheme.
"With the drivers, the crew and the technical nous behind us, we really have what it takes to become a top four team in this championship."