The Petone company was named the "quiet achiever" as it took out the export category at the recent Wellington Gold Awards, although the roar of the mufflers they help create can be heard around the world.
Sanpro recently secured a deal with French car systems company, Faurecia, the sixth-largest car systems manufacturer in the world with 280 plants across the globe.
Worldwide, one in four cars is equipped by Faurecia, including Volkswagon Group, Renault-Nissan, BMW, Ford, General Motors, Toyota, Daimler and Hyundai-Kia.
The deal could to be worth more than $25 million over the next five years to supply plants with its machines, which perforate mufflers faster than any others in the world.
Sanpro's machines perforate the tubes that are used in mufflers to help dull engine sound. Each costs $250,000 and takes four to six weeks to make.
Faurecia wanted the fastest muffler perforation machine on the planet; Sanpro's TPM4 can drill 100 holes per second, leaving behind bins full of tinsel-like metal coils.
Faurecia's head of special projects worldwide Randy Sprow said the company would be purchasing about 100 Sanpro machines over the next five years, for use at about 10 plants in the Czech Republic, India, South Africa and Brazil.
Sanpro's machine were the "global-standard" for muffler perforation, Sprow said.
"This is proven technology, it's the best we could find and it's innovative." Sanpro managing director and founder Malcolm Sanderson said the company typically sold 10 to 20 TPM4 machines a year.
The company's 12 staff include Sanderson's daughter and two sons.
Sanpro's lobby has a collection of about 30 mufflers on display which use its machines, from those used on John Deere tractors to a C-class Mercedes Benz, to the BMW X5 and a Harley Davidson motorcycle.
"One of our first machines produced a very unique part which is called a spiral lever and that's proved to have been very successful in the Harley Davidson and all the sports muffler manufacturers."
Harley Davidsons around the world have a muffler punctured by a machine Sanderson made in his Petone factory.
When the company started Petone was a major hub of automotive manufacturing, but as this disappeared, the company had to be reinvented to survive.
"While we made our own mufflers, we were building our own machinery. The machinery we built to make our mufflers turned out to be better than anyone else so we started producing the machinery and selling it around the world."
It was not until Sanderson travelled to exhibit his machine at an automotive show in Cincinnati in 1995 that he realised the perforating technology Sanpro had created was unique.
"We sold out of the machine that afternoon and we still had three days of shows," Sanderson said.
Sanpro now exports to more than 30 countries including Korea, the United States, Russia, South Africa, and Iran.
The first machine Sanpro Industries Sanderson sold is still running today, making millions of mufflers a year in Indonesia.
"I think we're quite capable of being competitive here in New Zealand with the technology that's available. I've always thought New Zealand should be the Switzerland of the South Pacific - hi-tech, low-volume manufacture."