what is better

I live in Bosnia, and in my place there is no highway.

I live in Bosnia, I drove in curve roads, a drive a Saab 9-3 2.2TiD '03 and my question is, is it better to drive cold engine in 3th gear on 2000rpm or is it better to drive in 4th gear at 1,500rpm.there is no hill, it is flat surfice

LOVE YOUR VIDEOS, can you make 3 times a week car talk show :D