Right, I just heard on the tellybox about a Mclaren Diffuser trick, and they do appear to have done something cheeky but technically legal (According to the clever boffins in the car thread). Whether that is the reason the rear looks quite planted, who knows.
I wonder if teams and the FIA are looking very hard at that. But then, the FIA left that particular loophole glaringly open so... Hopefully if it is a benefit, they won't rule it against the spirit of the rules, which they have done about things in the past. Although under Liberty stewardship, the FIA seem more relaxed on these things, as they are many things in the sport now.