SAO PAULO, Brazil - Williams driver Felipe Massa claims he was the only Ferrari driver in 2013 to work in the new driver simulator at Maranello Massa said he worked on the development of the 2013 car in the simulator and was the only driver to use it, claiming Alonso didn't use it. Massa admitted that Ferrari's biggest stumbling block in 2013 was the wind tunnel. Massa said: "Many times we saw that it didn't work as it should have. At most grands prix we had new parts, but they didn't work on the car. We began with a competitive car and ended with an uncompetitive one, which was the opposite of Red Bull."'I'M HAPPY'Ferrari parted company with Massa after an eight year spell that proved fruitless for the team. Massa made the move to Williams where he claims he is "happy".Speaking to a portuguese publication Massa said: "To be honest, I feel that I needed this change, and maybe it's the same for Ferrari. When time passes and the situation is the same, you end up losing motivation. "I'm very happy with the way I was received by Williams."