Leimer and the team will be hoping to build on what they've learned this week in the second three-day test, this time across country at the Circuit de Catalunya on March 5-7.
"I think we are in a very good place for next week's test in Barcelona, where we can test even more things as we also have a race on that track," Leimer said. "Overall, I am very happy with these test days - it went better than I expected and I think this is promising for the future."
While Leimer's new team mate wasn't able to make a proper year-on-year comparison in the status of the Racing Engineering car, Leal too said that the testing so far had been really positive.
"I am happy, as the race simulation went very well as well and we were good at managing the tyres," said the 22-year-old from Colombia. "In the end we found a very good solution. During the three days we improved the car and prepared it more and more to make me feel comfortable."
With the team based in nearby Sanlúcar de Barrameda, Racing Engineering are enjoying a small advantage over their rivals with the testing being held in their backyard in Spain.
"I like the track and I am happy as we had good results in Jerez and know there are still areas where we can improve," said Leal. "In Barcelona we will continue working from this base and the test there will be very important as it's a track we race on later this year."
The Spanish race weekend is scheduled for May 10-12 with GP2 supporting the F1 Grand Prix event. Spain is the third weekend in this year's race calendar following events in Malaysia and Bahrain, and will be held a fortnight before the jewel in the crown for both the F1 and GP2 seasons - in Monaco.
See full Tuesday test times
See full Wednesday test times
See full Thursday test times