I went the other route. I traded my Caymen S for the M. I am a huge Porsche fan and will probably pick one up again some day. But after owning both I think the M has more fun factor. The Porsche turned more heads though. The spyder would be a great car is Southern Cal. You can't go wrong either way if you ask me. Both are engineering marvels and fun to drive. Just don't be upset when M3's are looking at you in the rear view.
2014 Z4 35is - Valencia Orange Metallic with Alcantara/leather Black/Orange. 326M wheels.