Before 2012, you could take part in the pre-season tests before passing the crash tests. As long as you then passed the tests before the first race you were good to go. This gave extra development time and power (you could test prototype parts without needing to meet safety standards). You now need to pass all the tests before testing, so the car has to be "ready" sooner. You still see new parts and pieces on the car, but it can't be anything fundamental to driver safety.