The 949 wheels still look the same but now even better as roll formed and stronger as well as lighter, I would not hesitate to use them.
I have not heard of them cracking before and have know many to race on these wheels for a very long time. I know who built last seasons spec Miata national champ car and he runs them on his faster class race Miatas and is building a super nuts LS powered race car and sure he plans to run them on it as well.
---------------------
I have these on my car now, not my favorite spoke design but the were the best to fit over my BBK.
They are 12.8 lbs and roll formed, 15x9, 4x100, +35mm and will not fit the rear of a FiST without major mods.
I will sell them when the new Konig Helix is available in a month or so and get some spares at the same time. The Helix is the wheel I posted yesterday, second wheel out of three pictures.