Classic cars to invest in

As feel-good moments go, this one is hard to beat.

Skimming along the coastline in a classic coupe, soaking up the sun on a glorious afternoon and accepting compliments from fellow motorists out for a Sunday cruise. Not a bad way to make $100,000.

International classic car prices have accelerated rapidly in the last decade, to the point where plenty of sought-after models have at least doubled in value - including a handful of vehicles sold new in the last five years.

The Pagoda

Mercedes-Benz calls the car we are driving the 1969 280SL, but you may know it as the "Pagoda", an unofficial name stemming from designer Paul Bracq's decision to equip the car with a concave roof that takes inspiration from Asian architecture.

This magnificent example is based in the Mercedes Benz Classic Centre in Los Angeles, where many of the brand's most collectable cars are serviced. The centre is the sort of place people go after buying a $1 million-plus 300SL "Gullwing" to ensure it is in perfect condition - there were at least a dozen examples of the seven-figure supercar in for attention when we dropped by.

Mercedes Benz Classic Centre spokesman Constantine von Kageneck tells us how the soaring value of iconic 300SL models has dragged along less desirable cars such as the four-cylinder 190SL and more comfort-oriented 280SL.

A rising tide lifts all boats.

Five years ago, you could buy an ordinary Pagoda at auction in the US for $US25,000 - today that car is worth three times as much. It's a similar case in Australia, where international prices have rendered the classic 300SL Gullwing unattainable to all but the wealthiest of collectors, pushing quality 280SL examples over the $100,000 mark and the best closer to $200,000.

The lucky Melbourne collector who got hold of a 1969 280SL Pagoda for $27,500 at a Shannons auction in 2009 should be laughing, as these cars are accelerating at a decent clip.

Von Kageneck says the 280SL we are driving in California is worth $US150,000 or so. I believe him, having checked in on auction results in the US and abroad. The RM Sothebys auction house has a good record of Pagoda prices - the best 280SL examples struggled to fetch $US25,000 before 2005, a number that climbed to $US50,000 in 2010 and $US100,000 by 2015, with more to come.

Better yet, this mechanically reconditioned model is a honey to drive. The iconic convertible - pictured with its Pagoda hard top - soaks up bumps with ease, offering the sort of pillowy ride you will not find in new roadsters. Mercedes' classic in-line six-cylinder engine percolates along melodiously, the four-speed automatic transmission is surprisingly refined, the brakes and steering pleasingly accurate.

The Pagoda is a joy - I'm utterly smitten with the slim-hipped roadster. As are my Aussie travelling companions, who scheme up the best way to sell a classic car investment to their better halves once we get home.

It makes sense in a way - people who spent good money on a then-new Mercedes-Benz SL500 convertible in 2002 would have lost more than $200,000 in depreciation by now, while those who bought a classic Pagoda SL back then will have spent significantly less to start with before watching the car's value climb skyward.

Other classics

Mercedes models are not the only ones to increase in value. Air-cooled Porsches are probably the best example of cars that climbed vertically in recent years, while many Ferraris including the F40, Testarossa and 246GT "Dino" have also gone mad.

The Dino is a particularly telling example of the classic car investment craze.

Australia's Shannons Auctions sold a rough 1972 example in 2005 for $85,000, and a quality car in 2008 for $180,000. By 2014, two cars sold for $291,000 and $350,000 before Shannons' most recent example went under the hammer for $522,000. That last car isn't an outlier - Mossgreen auctioneers put a 1971 246 GT across the block for $546,250 in 2016, and other examples have traded privately for similar sums.

This sort of growth isn't restricted to Porsche and Ferrari - early Jaguar E-Type sports cars have appreciated markedly, as has Lamborghini's Countach, Aston Martin's DB5, Audi's Sport Quattro and many more desirable machines.

Modern machines with strong motorsport heritage built in limited numbers have also appreciated well, with once-affordable competition specials built for rally and touring car racing increasingly stretching out of reach.

Mercedes-Benz's wild-looking 1990 190E Evolution II can be found for sale overseas anywhere from $200,000 to $500,000, and BMW's equivalent (but much more common) E30 M3 is now a $100,000-plus proposition.

A beautiful example of Peugeot's 1989 205 GTI hot hatch sold in the UK for more than $50,000 in 2016, while RM Sothebys auctioned a mint Lancia Delta Integrale in 2016 for just shy of $200,000. Not bad for an Italian hatchback.

Car companies are becoming wise to the appeal of their heritage models and the flow-on effect it can have in new car sales. Lamborghini and Aston Martin have established new heritage centres, Ferrari has flown Australian technicians to Europe to learn how to service cars with superseded technology such as carburettors and mechanical fuel injection, Mercedes is expanding its classic centres and Nissan has opened a new Nismo parts service for the original Skyline GT-R.

New models

But no one does it better than Porsche. The brand's management of its own image, classic cars and motorsport is hard to beat - whether it is flying cars across the world from its museum, supporting the service and restoration of classic cars or releasing new models that tap into the brand's heritage, Porsche is on top of its game.

The manufacturer played on its classic appeal with a masterstroke of a new car in the 2016 911 R. Limited to 991 models around the world, the 911 R blends a motorsport-bred engine with an old-school manual transmission (that Porsche dropped from its top performance cars) and retro styling touches. Originally listed for $404,700 plus options and on-road costs in Australia, oversubscribed dealers were asked to hand-pick their most loyal customers for sought-after places in the queue to buy its most hyped model in years.

Plenty of people missed out, and Porsche was furious with successful applicants who decided to cash in on the car's appeal by quickly listing their cars for sale - one Australian owner asked for $1.2 million for an example that could have returned almost $800,000 in profit after one month of ownership.

Run-of-the-mill Porsches and Ferraris are unlikely to earn customers a profit in the short term - only limited-edition, race bred examples such as the Porsche 911 R and 911 GT3 RS or Ferrari 458 Speciale models tend to attract that sort of attention from buyers who miss out on carefully crafted demand. Some manufacturers require customers to have history owning less exclusive models before they earn the right to buy a limited-edition car, a strategy intended to discourage "speculators" from quickly turning around to "flip" rare and desirable models for a profit.

Porsche will have to play that game once again when it releases an updated version of the GT3 RS in the near future, as well as a wild, twin-turbocharged 911 GT2 that promises to be the most powerful Porsche sold in Australia.

Likewise, Ferrari will have far more customers than cars for the upcoming "Speciale" track-focused version of the current 488 GTB coupe, as well as potential issues surrounding its last non-hybrid V12 coupe, the 812 Superfast.

But those aren't the only brands to benefit from significant growth in the value of new vehicles.

Jaguar built 250 examples of its F-Type Project 7, delivering 10 to Australian customers no doubt thrilled to see that the model's value has increased by 50 per cent in the UK.

Similarly, McLaren's limited-edition 675 LT coupe and convertible have both increased in value following their release, as has the ultimate Black Series version of the Mercedes-Benz SLS AMG gullwing.

While it's impossible to say exactly which future models will experience a guaranteed increase in value, a good rule of thumb is that limited-production models that represent the end of an era - such as naturally aspirated cars - are a good starting point, as a models with strong international appeal.

Australian models

If you're an Aussie V8 fan, look away now.

Much of the value in collectable cars in Australia comes from overseas interest as high-end dealerships such as Sydney's Classic Throttle Shop and Melbourne's Dutton Garage regularly buy and sell cars from the UK, Asia and America for customers at home and abroad.

While that 911 R is a desirable car on every corner of the earth, the last Australian HSV GTS-R W1 - a car that costs $169,900 plus on road costs ($200,000-plus on the real world) - has limited appeal outside our shores.

Shaun Baker, general manager of Dutton Garage, says high prices paid for Australia's last Ford Falcons and Holden Commodores represent "a very big bubble that will burst".

"Australia is a very small market," he says.

"Don't jump on the bandwagon thinking that you're going to make money."

Holden offered buyers of its final Motorsport, Director and Magnum V8-powered models a chance to have their cars delivered in protective plastic. But Baker says they are "rubbish" investments compared to cars with a global appeal.

Classic Throttle Shop spokesman Jay McCormack diplomatically says he is "not quite sure" of the investment potential of late-model Holdens.

But both salesmen are convinced by high-quality European prospects.

"These cars are commodities now. It's sad, but that's the way it is," Baker says.

"The demand will always be there. People are buying them as blue chip investments. They're not driving them - they look at the clock.

"This isn't mum and dad in the suburbs, these are blue chip investors."

McCormack agrees, saying potential investors should consider cars with appeal beyond Australia's shores. McCormack says Japanese models from the 1990s have strong potential for the future - cars such as Subaru's original two-door WRX STI models as well as Australian-delivered Nissan GT-Rs and tech-laden curiosities that may strike a nerve with millennial enthusiasts in years to come.

"Cool, iconic Japanese cars from the late 1980s and early 1990s are seeing a larger rise - definitely Nissan products and Toyota products which are quite cool," McCormack says.

"That's probably where a bit of the focus is."

Fundamentally, McCormack says people should buy something they enjoy first, because "there is no proven science or formula to buying something that's instantly going to appreciate".

Five recent new cars that increased in value:

2013 Mercedes SLS AMG Black Series

New: $639,000 Now: $1.3m

2014 Ferrari 458 Speciale A

New: $635,000 Now: $1.5m

2015 Jaguar F-Type Project 7

New: $339,610 Now: $450,000

2016 Porsche 911 R

New: $404,700 Now: $1.2m

2016 McLaren 675 LT Spider

New: $672,500 Now: $950,000

(Current values guided by recent sales listings)

Dave's choices: Sub-$100,000 enthusiast cars I'd invest in.

What: 1994 Dodge Viper RT/10

How much: $49,000, Gosford Classic Car Museum

Why: The Dodge Viper was a genuine poster car for my generation - ranking alongside icons such as the Ferrari F40 and Porsche 959. It's all about that massive 8.0-litre V10, the side exhausts, manual transmission and total lack of driver aids. I love the Viper's cartoonish looks, motorsport pedigree and the challenge of driving one well.

What: 1991 Nissan Skyline GT-R

How much: Est. $65,000-$75,000, Shannons Auctions

Why: The original Skyline GT-R is a true icon. The Bathurst-winning machine smashed Aussie V8s to forge a reputation as a giant-killer at home and abroad. This original Australian-delivered example is one of 100, making it a rare car with genuine motorsport history and a strong international following thanks to the likes of Gran Turismo.

What: 1993 Porsche 968 Club Sport

How much: $85,995, Classic Throttle Shop

Why: If you've got $100,000 to spend on a classic Porsche and can handle having the engine at the front of the car, why not consider a rare 968 Club Sport with the motorsport option pack - it's like an early 911 GT3 RS, right down to the factory fitted roll cage, fire extinguisher, adjustable suspension and fixed-back seats.

Also consider: Toyota Celica GT-Four, Subaru WRX STI Coupe, HSV VT GTS.