I find my car runs better in the colder weather. Currently on setting 1 +3 with no issues at all covered over 2000 miles like this so far, before the drop in temperature was getting coil light on settings +3 and +2...so colder weather's a win win for me mate.
I've always ran mine on 3+2, few hissy fits at the start but all grand over the past 10k.
Might upgrade to the CRD3 after Christmas.