For any team it is a major task to change from one engine supplier to another. But with the knowledge gained from Toro Rosso using the Honda Formula 1 engine last year, Red Bull's challenge will be just that little bit less complex.
From one engine manufacturer to another, there will always be subtle differences in how they measure the heat rejection from the oil and water.
But the new Red Bull, as with any of Adrian Newey's cars, is as tightly clothed as possible. I'm pretty sure this means the cooling requirements are not too far away from those of last year's Renault unit.