The idea is basically to reduce the effect of the coupling of the diffuser and the rear wing. What about reducing the rake angle of the cetnral tunnel of the diffuser and making the rear wing anhedral so the middle is higher than the ends? I have a few very poor edits of what I mean.
First picture is the RA107 without anything edited.
This picture is an edited version, as you can see, not very good, but you can still work wonders with paint
This one is from above.
And finally this one is from behind, I think scarbs did the original picture I edited.
