as above, my options are:

Motul 8100 X-cess SAE 5w - 40 (100% synth)

Motul 8100 X-max SAE 10w - 40 (100% synth)

from my understanding 5w means that it has less viscosity at -18 C than the 10w. so with 5w its easier for the engine to start up relative to 10w?

cheers