Initially I thought Cayman S. I don't think there is any debate that it's the more desirable car, and with good reason. However, I think I would choose a BRZ (over the FRS, hate the association that comes with the Scion badge). Reliability is in another class vs a used Cayman S since you'll have the warranty, and you can make the car truly yours with mods with the leftover cash.
If you do go the Cayman S route I won't blame you though. I would just make absolutely sure it's a clean example. A 3rd party PPI is absolutely necessary with a car like this, and make sure you're the one paying for it.
Current: 2011 BMW e92 m3
Past: 2012 Audi TT-RS
2009 VW GTI