I think Mercedes is running spec2, but that is just a hunch. As GPR said, i think some of the aero updates are linked to the engine too.
Anyway, i think Mercedes is strong and will be stronger than Ferrari. They’ll be ahead in QF and the race. I think Bottas will be strong, but might be edged in qualifying. If he can nail it though, i think he could win this weekend. It will be crucial who nails it on the US as that seems to be the tire that they struggle most to get into the tenperature range. It will be warmer tomorrow though. Hamilton does look on form though.