mobil 1 motorsport 15w 50 is fine for all year round, i ran my old s2's on it for 3 years each and they were 200bhp daily drivers
silkolene pro s 5w 40 is what i use in my s1
Personally I wouldn't use anything as thick as 15W on a daily driver. On a cold day it'll take several seconds for the oil to reach the head/tappets and the bearings of the turbocharger.
It says Motorsport on the tin, yeah, fair enough. But in motorsport you usually don't start a car several times a day at -5 degrees.