The FIA has confirmed Ferrari has spent the most engine development tokens over the winter after releasing the token spend of all four manufacturers ahead of the start of the 2016 season.
The token system is designed to control spending on engine development and puts a value on updating various engine components. Each manufacturer has 32 tokens to spend over the course of 2016 -- including pre-season and in-season updates -- and Ferrari has spent the most ahead of the first round.
Ferrari - 23 tokens spent (9 remaining)
Mercedes - 19 tokens spent (13 remaining)
Honda - 18 tokens spent (14 remaining)
Renault - 7 tokens spent (25 remaining)
After making significant progress with its power unit in 2015, Ferrari has rejigged the layout of its engine and energy recovery system again this year as well as making a significant amount of upgrades.
Mercedes has continued the development of its 2016-spec V6 turbo, which it first introduced in its works cars at the Italian Grand Prix last year.
Honda has focused on big changes to its turbo and MGU-H over the winter, but still has just under half of its token allocation left to spend.
Renault, which is focusing on improvements to its internal combustion engine, has spent just seven tokens so far with huge potential for further improvements later in the year.
Components are weighted at a value of either one, two or three tokens, with a combustion upgrade, for example, costing three tokens. Changing every component on a power unit would come to 66 tokens, but 32 tokens offers significant scope for upgrades over the course of the season.