Renault wanting to lose a deal with somebody, and Toro Rosso wanting to pick up a Renault engine, combined with their relationship with Red Bull would suggest that both Williams and Lotus will need new engines. I don’t know what the current contracts are, or how long they last, but I’d expect something like:
Williams to switch to Mercedes, given the rumours, I guess it would make sense, especially with McLaren no longer using their engines. I’ve heard (I think from Autosport) that Honda won’t supply anyone else in 2015, so that could mean that Lotus will have to wait for 2016, if they want Honda. Sauber are likely to keep with Ferrari, with Marussia making the switch as well.
So, for me the question is what Lotus will do, if they do part with Renault. Ferrari or Mercedes for the next couple of years?