After running six different drivers in their first campaign in 2013, Downton have stuck with the duo since the start of last year, and this deal means the pair will be race together for a total of four consecutive seasons.
'I'm very excited to announce that we've been able to extend the contracts of both Nathaniel and Marcus for two more years, keeping them here at Downton until the end of 2017,' announced team principal Bradley Downton to a packed gathering at a press conference held in Sau Paulo, Brazil - the scene of the current third round of the Championship.
'Both drivers are young and hungry to do well, as our we ourselves, and they push each other, making them a formidable pairing. It's also important to have continuity within the team as we strive to push towards the top of the grid.'
Both drivers were also in attendance, with Thunder saying, 'I'm delighted to continue racing with this team. They first brought me into the series when I was just eighteen in 2013, and I've grown with them. I really hope we can use this as a platform to move forwards, I'm excited for the future.'
Powers added, 'I'm happy to extend my contract with Downton. The team have been superb since I joined, and they're super motivated to do well, and environment that really suits me. I thoroughly enjoy working with Marcus as he's a great laugh but super competitive and serious when necessary, and the whole team has a fantastic atmosphere and spirit.'
The announcement rules Kiara Thunder out of the running for a seat with the team, after Downton earlier confirmed she would be racing in 2016. This likely means a deal has been struck with another time - rumoured to be DS Mathershaw - or plans have changed.