McLaren and Honda are very bullish about the performance of the new Honda power unit, aren't they? Being in possession of Mercedes engines and performance data, McLaren might be forgiven for not egging Honda's prospects. And if there was any doubt in their minds, forgiven for not chasing an Alonso, Vettel or a Hamilton. If Alonso joined McLaren and the Honda was a pup, the fallout would be significant.
Everyone makes a lot of the advantages of the power unit, forgetting that a significantly underpowered Red Bull has dominated F1 for four seasons.