I've been thinking about this some more and I reckon that Red Bull are possibly also heading toward a solution like this.
Here's some things I've noticed:

I know it's not uncommon for the floor of an F1 car to be unpainted CF, but I notice that the Renault has apparently the same type of surface all the way along the edge of the sidepod, widest near to the exhaust exit where the fumes are going to be hottest.
Well, I took a look at another team running a Renault engine and sure enough:

If anything, the Red Bull has it's heat sheilding (if indeed that's what this is) even higher up on the sidepod. Could it be that Red Bull are planning on sending more of their exhaust over the floor than Renault?
Second thing I noticed was that the Renault has these vertical fences placed in front of it's rear wheels.

Presumably, the idea behind this is to steer the hot gases inboard in order to ensure that they pass over the diffusor and are not sent in front of the rear tyres.
Well, shock horror, guess which other car has these too:
What do you guys think?
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