At the Tarawera, Sa will join Suter in a line-up that includes the current World No 1-ranked runner, Olympians, world record holders and more than 20 past and present national champions of several countries.
The 100km run from Rotorua to Kawerau is the brainchild of Paul Charteris, a local ultra-runner himself. In its first year, the race attracted 67 people, only one of them from outside New Zealand.
For the sixth race, more than 850 runners from 28 countries will line up at the start among the giant redwoods of Rotorua's Whakarewarewa Forest.
"It means that the Tarawera Ultramarathon will feature possibly the deepest field ever assembled for an endurance event in New Zealand," said Charteris.
It's an audacious claim for what is often considered a niche sport in New Zealand.
However, the list of entries is the who's who of the international endurance running community.
Carlos Sa will face current World No 1 Rob Krar from Canada and Sage Canaday from the United States, the defending Tarawera champion.
They'll be up against Mike Wardian and Michael Aish (US), Martin Gaffuri and Stephan Quentin (France), Manuel Lago (Brazil), Yun Yanqiao (China), Japanese phenomenon Yoshikazu Hara and Australia's best ultra runner, Brendan Davies.
The top Kiwis include Vajin Armstrong, Marty Lukes and Scott Hawker.
There'll be similar intense competition in the women's field between Australia's Beth Cardelli and Shona Stephenson, Meghan Arbogast from the US and Japanese endurance running star, Tomoko Hara.
Many of the top international runners are capable of sub 2:30 marathons and have Facebook fan pages with 30,000 or more followers.
And the top 20 runners in the field have won several hundred races between them.
"So it's fair to say that the absolute elite of world trail ultra running is coming to Rotorua," said Charteris.
Trail ultras are very popular in Europe, Japan, Hong Kong and the United States, where top athletes are treated like rock stars.
Events attract massive audiences and this has captured the attention of corporate sponsors.
"They're pumping serious money into the sport, to keep up with its potential," said Charteris.
The evolution of the Tarawera Ultra event reflects the growth of the sport both in New Zealand and internationally.
And the increasing status of the event and quality of the trails in New Zealand was officially recognised last year.
The Vibram Tarawera Ultramarathon is now part of the Ultra Trail World Tour.
This 10-race grand slam of ultramarathons includes some of the very best endurance races round the world.
On March 15, all eyes will be on New Zealand.
As well as enhancing the country's reputation as a superb destination for trail running, the Tarawera Ultra event will also inject more than $1 million into the local economy.
The race will start in Rotorua just before dawn and finishes 100km away in Kawerau.
"However, we do have 85 and 60 kilometre options for those slightly less bonkers," Charteris added.
