Short term, I don't think so. The 370z already has the stigma of overstaying its welcome without any significant updates nor reduction in MSRP. Long-term it just depends on how history views the car. The GT-R also has its issue of getting pricier each year (more than what I'd say it's worth) and is artificially holding value on the used market. I was actually looking around the GT-R forums because I'm loosely interested in getting a used MY17+ GT-R if the prices come down more. The exception would be NISMO and potentially the "Track" trim levels due to their rarity, but your normal "Premium" GT-R is probably going to not increase in value unless all of a sudden the demand skyrockets. The GT-R, while popular, will likely not get the MkIV effect. The exception here would be pristine low-mileage, non-modified examples. Any increase on those 2 cars has got to be long-term imo. Most cars have to "bottom-out" on the depreciation curve before they can start to appreciate and that also hinges on demand for the car vs. supply. I think the GT-R has the better shot at appreciating long term but there's many factors that play into that.