Drive the Porsche before you pass any judgement on it. Comparing the driving feel to that of a 335i, the Cayman S feels like a much more stable and capable car. It's a very rewarding car to drive and I think it looks awesome. If your dad chooses it, make sure you get the optional LSD.
The only qualm I have with the Cayman S is that once you option it up a bit, the price starts to creep into 911 territory...