[neor]

Part of the agreement is that Ferrari engineers are helping the FIA to police the other engines.

The engineers on the payroll at the FIA don't have the time/resources/knowledge to judge the legality of these insanely complex powertrains.

All manufacturers were forced earlier this year to provide detailed info about their Energy Recovery Systems, rumors are that Ferrari suspects the Mercedes ERS to make use of loopholes so Ferrari lends their engineers to the FIA to research the data provided on all engines.

Close some of those loopholes with a Technical Directive (Basically a clarification of the rules, which takes immediate effect) and you can slow down your opponents with immediately.

[faichai]

Source? I find it hard to believe FIA would give Ferrari privileged access to other teams data.

[manojlds]

Teams give FIA the data and Ferrari gives pointers and other help. The sensitive data is not shared with Ferrari.