Instead the pair, who met buying antique dining chairs 15 years ago, are now Australian motorsport's classic couple.

The unmarried pair, who refer to themselves as husband and wife, have succeeded in the emotionally-fuelled sport with their mantra: "Love you – bigger together".

In matching outfits chosen to suit the colours of their 1985 RX7, Faux and Mihalovic last week collected the prize for outright victory in the classic category of Targa Tasmania, Australia's biggest on-road rally.

Topping it off, the car was developed and crewed by Canberra's Jon Waterhouse of Reliance Automotive, Fyshwick.

"When we first did it, Jon who built the car said 'this will be really tough to survive as a couple, doing it together','' Faux, 65, said.

"It is immensely challenging and we've had huge barneys over the years. If something goes wrong with a mate, you can have a screaming match and then a beer at the end of the day. If it all falls apart, you find a new mate.

"But you can't do that with your life partner. We've got a huge amount of mantras. But if we have a big blue, we have a letting off steam exercise and we both say 'love you – bigger together'. It's about reminding each other that I can add value to Therezia's life and she can add value to mine.

"So rallying and racing has fortified our relationship by about 300 per cent."

Faux developed his Canberra business, Fox Antiques, which is where they first met. He was 40 before he took up motor sport as a hobby.

But it was only in 2006 when his navigator relocated to Europe that Mihalovic volunteered to sit beside him. She was a natural, Faux said.

"She knew if she didn't get in the car then I'd get too good that she wouldn't be able to learn with me. So she said 'I want to navigate'.

"[Competitors] thought it was a little lady, now it'd be a tea-party, that'll be the end of him. But ever since Therezia got in the car we've been starting to get closer and closer to the big prize ... she's brilliant at it, she has no fear."

Mihalovic, who works in education in Tuggeranong, says they are perfect partners.

"He's the most intelligent man I know, in a sense that he is very methodical, analyses things and comes up with a plan to achieve,'' Mihalovic said.

"Barry's a good driver, he doesn't get the red mist. I know he's my partner, but if I didn't feel comfortable I wouldn't be sitting beside him. As a navigator, you've got to have the utmost trust."

The pair were trailing by 23 seconds going into the fifth and final day of Targa. But wet weather on the final day gave them their chance, when driving rather than horsepower determined the result.

"In the wet, we just drove the living daylights out of that little car," Faux said. "At 180kmph, the windscreen wipers lift off and you go to blur ... there were stages we were going more than 200kmph.

"You've got to keep your brain in front of the car, you've almost got to be seeing into the future."

Although in antiques his entire career, Faux said that wasn't what attracted him to classic cars.

"I appreciate the classic cars because a modern car will cost you from $500,000 up to $1.5million. My theory in life is, if if you're not having fun in the tinny you'll be just as miserable in the mega-yacht. We love our cars."