The first is buying a property only for its huge block size in order to build a massive workshop and garage far bigger than the house. The second is to be infatuated by tools and steel fabrication equipment.

Both Adam and Kylie Perry sheepishly admit to both.

For years, the Canberra couple have been the quiet achievers of the local car modification scene, starting out their relationship in the most unorthodox way of co-building a Holden one-tonne ute, entering it in the famous annual Deniliquin Ute Muster, and carrying off first prize.

But when the knot was tied and the workshop built, the project which cemented the couple's reputation as among the country's elite car builders was Tailspin, an FB Holden coupe that was built back to front: the tailfins went to the front and the bonnet became the boot.

"We wanted to do something that no one had done before and saw this sketch of the idea in a magazine," Ms Perry said.

"We thought: 'we should have a crack at that'. And the project took off from there."

A Frankenstein's monster of car construction, the lower metalwork on Tailspin's bodyshell was refashioned from five separate cars, then a roof from a Nissan Skyline coupe grafted on top.

For a couple untrained in the arcane skills of car building, yet keen to learn and dedicated to the job, Wollongong car master craftsman and former Summernats grand champion Howard Askill provided the tuition.

"Howard would come up to Canberra and bring his tools and welding equipment and show us what to do, then he would head home and we would then push on with it; that's how it progressed," she said.

The fully engineered 14,000-hour car project won Melbourne's Motorex grand champion and finished in the top three at Summernats.

Even now, some six years later, Tailspin remains the ultimate automotive trick-of-the-eye effect, like the fabled "pushmi-pullyu" created by British author Hugh Lofting in Dr Doolittle.

"We take it out for drives and the occasional show and it still does people's heads in," Adam Perry said.

The customer demand for the Perrys' work far exceeds their ability to keep up, especially each with fulltime jobs and now with two small children. They are working on their second Chevrolet Camaro as well as a modest 1.5-litre Datsun Fairlady, which will be a daily driver built for Kylie Perry's grandfather.

Like hundreds of Summernats entrants driving in all the around the country, Christmas provided only a briefest of break before it was back on the electric buffer to have cars primped and preened for one of the biggest modified car showcases in the country at Exhibition Park next weekend.

"We were never going to have this particular Camaro ready for Summernats this year but there has been so much interest in the building of the car on social media that we were asked to take it along to show the progress," Kylie Perry said.

"But just to have it looking good has taken about 40 hours of polishing so far, and there's still more to do."