Discussing with a friend yesterday (absolute F1 fan for years but with low technical background, just as I am) we ended up explaining the Renault consistent and sudden improvement the following way:
Renault and RBR, as partners, made an agreement. RBR helps Renault to improve their car giving them some of the "secrets" they have for this year. Win-win deal as RBR needs an outsider to take out some championship points to Ferrari and MacLaren.
Arguments: some similarities on both cars, no F-duct on both of them...
Does it make sense to you ? Or should I go back to therapy???
Thanks to all. VAMOS FERNANDO!!