Ferrari is travelling to Australia early this week with a few less horse power in the luggage.
The Italian team was arguably the surprise of the 2015 pre-season, with much of its improved pace credited to a much better turbo V6 power unit.
But Gazzetta dello Sport reveals that Ferrari ultimately decided to take a "more conservative" version of its 2015 engine to Melbourne.
That is because, although clearly better, question marks about the reliability of the fully-upgraded new engine remained ahead of the first two races.
Gazzetta stated: "Telemetry from the tests raised a few doubts about the latest version of the (works) Ferrari engine, while there were no such concerns with the 'customer' version."
"The SF15-T may therefore have slightly less performance (in Melbourne) than what was seen in the last hours of work in Barcelona," the Italian report claimed.
In 2015, each driver is limited to just 4 'power units' for the entire season, down from five engines last year.