What will the cars sound and look like? Will the engine manufacturers get it right? Which team boss is already looking concerned?
These were just some of the questions AUTOSPORT travelled to Spain with, and we got a lot of answers.
As ever with pre-season testing, there is still an awful lot to discover, but here are the main things we learned from the first F1 test of 2014.
RED BULL FACES ITS BIGGEST CHALLENGE