Originally Posted by rondocap
I want to be excited and have fun - may even start track days later on. The z06 is likely too fast for street use, while the other 2 are easier to rev out and push to a reasonable limit.
I'd recommend M3. Here is why - both new Z06 and Cayman are getting much better in the new generation, practically in every way, without losing anything from their identity. So you still have a chance to experience all what those cars have to offer but in a better way in the future. M3 is losing it's glorious NA V8 with stratospheric redline and racecar sound. The next one is not going to be the like that (it's still going to be good, I'm sure).
Also, it's a great car to start tracking - very comunicative and predictable, and very easy to drive. It tells you about everything you do wrong but does not punish too hard. Corvette would punish you in a big way, so you may end up not being able to take it to 9/10 for years - that's one of the reasons that in almost all track videos you see M3s passing tons of Z06, even though Z06 is a much faster car. Cayman is a different beast - where M3 is a sportscar built on a road-car platform, Cayman is a road car built on a sportscar platform. Just one example - it boosts the brakes for you if you release the throttle rapidly, just like a soccer-mom-focused van would. I hated it on 335i, and was suprised to see it on Cayman - the same effort on the pedal can mean different things in different context. On M3, you have exactly the same brake feel and reaction on every application until you cook the brakes - it's all you, not some gizmo. I feel that M3, even with it's extra weight, is still more "sincere" in it's communication compared to Cayman. They improved on this in the new Boxster, so a sign of good things to come for this platform in general (hence my recommendation that you can try it later). Another thing is that you can drive M3 on a track like finesse-focused car, like a muscle car and like a crazy hooligan car. You do not get all the three options with any of the other two choices - Z06 is close, but it takes a lot of experience to achieve finesse with it or to safely drive it as hooligan car on the track.
Another reason is that, at least for me, M3 is the most complete out of the 3 choices. When I was choosing cars initially when I got M3 and then later when I was looking for something new to replace M3, there was always something missing in Cayman and Z06. No need to list those things - they are widely known. There was nothing in M3 that would get me angry or disappointed - you do not feel like you have compromised on anything nearly as much as with other cars. So if you are going to spend a lot of time with the car, it's something to keep in mind. For a toy it may not be as important - you just love them for strength and ignore weaknesses.