Highcroft's new signing, Marino Franchitti, was instantly competitive driving the team's new Honda ARX-01c, setting the fastest LMP2 time at the Sebring winter test yesterday.
The Scot, who scored two LMP2 victories for Dyson Racing in the American Le Mans Series last season, clocked the fastest time of 1m48.263sec over the two-day session, sharing the driving with his new teammates David Brabham and Simon Pagenaud.
Despite changing weather conditions disrupting the test, the new team finished in the top three in all four sessions, and the drivers were impressed by the car's performance.
"It's been a very positive day for everybody here and we are all very happy with the way things have gone." Franchitti said.
Former Le Mans winner and reigning ALMS LMP1 champion Brabham added: "The car ran very reliably over the past two days, which will not only help us in preparation for Sebring, but the entire season. The new car is very different from last year but I think we are in reasonable shape."
Final testing for the Sebring race is set to start on March 15 with qualifying for the American endurance race taking place on the Thursday of that week.