Did think about a C6 as well, just figured the z06 sounded like a better idea as I can keep it longer as my abilities increase or I plan to track it in the future.
I will let the idea mature in my head. The m3 is the best balanced driver, the z06 the brute power - and I guess the porsche falls somewhere in the middle.
I'd like a 09+ 911 s too but they are a bit out of my price range, and I feel the Cayman/boxster give you a good performance bang for the buck in comparison.
Definitely interesting for me coming from a 335i and base Boxster already - great cars in their own regard but just a notch below those aforementioned cars in terms of performance and engagement.