I've heard a lot of people talking about the future appreciation of the G8 and SS. I don't see it specifically because neither one is particularly good looking. Almost every single car that has appreciated has done so, in part, because of it's design. I made
a post a while ago where I made the argument that long term price appreciation depends on these three factors:
1. Beauty
2. Rarity
3. Significance
Of your list, I think the Porsche 993 is the best candidate. Unfortunately they have already gone up pretty high, the rarer models are trading for some scary numbers (more on the 993 later). R34 is probably next, though prices are going to be extremely volatile, and its hard to predict where they will land. They aren't legal in California (and might never be without significant work), so it limits the resale market, somewhat. Some other candidates I think are compelling cases:
Porsche Boxster Spyder (987 model. These are a bargain at the moment. I've seen some for under $60k even. Surely they have enormous upside potential)
The trifecta of "last of the old school" Ferraris:
Ferrari F355
Ferrari 456GT (I've seen these for less than $50k! A V12 Ferrari with a gated shifter!)
Ferrari 550 (These, especially, are going to hit 7 figures in 20-30 years, I'm almost certain. I never understood why people didn't see these as absolutely beautiful when new...as they are starting to now)
I already suggested the Dodge Viper, primarily because they are so cheap now.
Mercedes CLK Black (First generation)
Mercedes SLS AMG (Gullwing doors! - These have stopped depreciating, from what I've seen)
Assorted Flotsam & Jetsam:
Alfa Romeo SZ - Either extremely ugly or extremely cool depending on your eyesight, but they appear to be gaining strength on the US Market. Not CA legal.
Lancia Delta Integrale - Been seeing these pop up for sale out in the Bay Area. Again, not CA legal, but should be a long term gainer for sure.
Subaru 22B? I have no idea what these are doing, and I've never seen one for sale in the US. But its gotta be a solid investment. In a similar vein....rarer versions of the Mitsubishi Lancer Evo V could be a strong investment.
Detomaso Pantera - Old and not EFI (though, they are frequently modified to have it). But they have an intriguing legacy and quite good to look at. Should be reliable as a tree stump too.
As a general piece of advice: I wouldn't worry
too much about the maintenance on Porsches. They are generally well built cars and actually not too difficult to work on. This is especially true of the pre-996 cars. Parts are more than typical cars, but not orders of magnitude more. Engines can be expensive to repair or replace, but they are built well (with the exception of the IMS issues on the early water cooled cars) and take a lot of abuse.
I feel like I kind of missed the train on the 993 (I was still in college when they started to explode in value), but every time I see one I generally tend to think of it as the pinnacle or ultimate expression of sports cars. Modern enough to be genuinely good to drive and reliable, but not too modern to be disengaged, timelessly beautiful, pedigree. The 993 has it all, even in base Carrera 2 form. I still see a lot of them (I see several, daily) being daily driven out here in CA, so I gather they are durable and reliable as well. A Ferrari would be more special...but not as reliable. The Japanese cars are rewarding to drive...but I don't think as special to own ultimately.
Anyways, that's my full bag of pennies.
edit: This video made me pine so much for a 993 that I bought a 986 as a substitute:
So purposeful (size, cockpit, seating position, drivetrain layout, dynamics) and so, so beautiful at the same time.
These BFG tyre might be better than the Toyo with soft side walls but then the ride will be stiffer if the BFG has a stiffer wall being more track orientated.
