Well it was Vettel's choice to go with an old spec, looks like it was the wrong call at least for qualifing.
A rather interesting grid for tomorrow though. Even though Mercedes line up 1 and 2, I suspect that their race pace will be slower than the other leading teams. After all the extrra speed they gain from stalling the front wing as part of the DRS is only useful when they can actually use the DRS.
Tempature alters the pace of cars as well, some cars run better when it's cooler others when it's hotter. Tyre wear etc..