Richard Petty Motorsports teammates Marcos Ambrose and Aric Almirola completed a successful two-day test session at Sonoma Raceway on Wednesday.

It marked the first significant test for NASCAR's new Gen-6 car on a road-course, and the first time the new car has visited the 10-turn, 1.99-mile Sonoma circuit. Ambrose completed approximately 75 laps, while Almirola completed 100 laps, all in race trim. Lap times were not available.

"We always want to try to get an advantage on the competition, so we feel like it's been worthwhile to be out here and hopefully it will pay off for the race," said Ambrose, who won the pole in Sonoma in 2012. "We're happy with the progress, but we would love to be faster always. We're confident that we've learned a lot and we'll come back with a better package in June."

Ambrose and Almirola will return to Sonoma Raceway for the Toyota/Save Mart 350, June 21-23. This year's event marks 25 years of NASCAR Cup racing in the Sonoma Valley, but while the raceway looks back on its history with NASCAR, fans will also enjoy exciting changes on-track.  In addition to the new car, NASCAR has modified the qualifying procedure for road courses in 2013. In Sonoma, drivers will face two practice sessions on Great Clip Fast Friday, with group qualifying slated for Lean1 Pole Day on Saturday.

"I love coming to Sonoma.  It's fun," said Almirola. "The track is challenging, to say the least, but it puts on a great race and the track always draws a big crowd, which is fun for us drivers when we come to a track with so many people."

"This is one of the toughest road courses you can come to with these cars," added Ambrose. "They are very heavy and powerful and this track is very tight and burns up tires, so there's a lot going on out there and it's a real challenge for the drivers and team, but I always like to go road racing."

All of these elements will come together for NASCAR's 25th annual visit to the Sonoma Valley, June 21-23.