Its hard to tell what the market is doing at the moment. Maintenance is fairly reasonable aside from major services (transmission oil), tyres and brakes, and I wouldn't expect this to affect car values..
What will be interesting is to see how much those 2009 model R35's out of warranty will go for in a years time - since the main concern with 2nd hand stock + modified GT-R R35's is the transmission failures (solenoids, gaskets, pressure sensors, shift forks, circlips, etc, etc...) and bell housings... These 2 points will be the main depreciation concerns as Nissan asks for $23,000 rubies to swap one out outside of the warranty period. I think it's just a shame that Nissan don't offer the same warranty here as the US (5 years) and there's still no "official" warranty extension available to purchase (rumours that Allianz was working with Nissan on offering an extension to owners seems to be 100% BS at this time).
For sure if the belly falls out of the "out of warranty" 2009 models, I'll be looking to move mine on around the 2.5 years ownership mark
Alternatively, I am not sure if you can cover "specific" parts of a car with vehicle insurance for mechanical failure, so that you don't have to have $23k sitting in a bank account in the unlikely event a transmission fails....