... up to half their price two years ago.
The interest is fed by the strong Australian dollar's exchange rate with the US currency, and depressed prices for older cars in the US in the wake of the Global Financial Crisis and the current US recession.
Car transporter Cargo Online boss Steve White said there had been "a lot of movement'' since the Australian dollar rose to US80c and though imports are stabilising, his relatively small business is still moving 200 cars a year.
But he said while classic cars were still popular, new government rules on importing modified cars have seen a big drop in some muscle cars.
US-based specialist car dealer Lee Wolff of Vintage Motor Car in Ohio said he is "getting lots of inquiries from Australia.''
"The collectors that want great cars will pay fair market value. If it is something special they usually are not concerned about the exchange rate, if it is a vehicle they want,'' he said.
"The prices in the US collector car market are generaly lower than in recent times, but good quality cars continue to stay strong. "It is always better to purchase a good quality car that has been restored as the cost of restoration is so high.
'' Perth enthusiast Reg Toohey is just one who found a bargain in the US. His 1956 Cadillac Eldorado Biarritz Convertible was bought for about $100,000 and arrived from New York to Perth just before Christmas. Mr Toohey said the price was about half of what a similar car would have fetched 10 years ago.
"The car had been totally restored - down to each nut and bolt - and had travelled only 1600km since,'' he said. "It is in immaculate condition. I was lucky that the Vintage Motor Car company I dealt with in Ohio had an honest appraisal of the car.
"I never wanted an older car because I thought they would be unreliable. But I participated with a business associate in the Peking to Paris race in 2010 in a hastily-bought 1935 Bentley and over 15,000km, it had no mechanical faults and only one puncture.
"So I got hooked on old cars, looked for a 1959 Cadillac - the one with the huge fins - and found this fully restored 1956 Biarritz. "You have a lot of fun with your family in these. Everyone from bikies to little old ladies love to see these cars. I know I'm just this car's caretaker - I hope it will go to other people after me who will enjoy it as much as my family does.
'' Mr Wolff said Australians especially like limited editions from around the 1950s, he said. "Any good quality car is a candidate but Aussies like cars that were made in limited production. "The Cadillac Biarritz is a perfect example. The `56 Cadillac is a limited production convertible. It is 6m long and is sought after worldwide.
"They were mostly special ordered from the General Motors dealer for movie stars, sports figures and dignitaries. '' Though rare, the Biarritz is the second in Perth - the other is a 1958 model owned by a private collector - and typifies a flow of American classics out of America.
Of the 84 known surviving 1956 Biarritz cars, 50 are outside the US. Mr Toohey said enthusiasts should spend time researching cars and costs.
He was surprised that though the government charges no duty for an imported car, there were GST - at 10 per cent - and Luxury Car Tax (at 33 per cent) charges in addition to the cost of freight.
He estimates it cost almost $30,000 above the car's purchase to have it parked in his driveway. Department of Infrastructure and Transport data shows more than 11,000 vehicles were imported in 2010, the most popular being Ford Mustangs.
However, showing that Australians aren't interested only in class cars, within the top five vehicle list was the Piaggio Vespa scooter.