So are all cars to be honest but at least the s3 gets up to running temperature very quickly (exhaust heating the coolant). It takes a good 15 miles or so of driving before the oil is at operating temperature and that makes a difference to the economy as well (although not as much)
I always wait for the oil to be at least at 80° before properly driving. I see a massive difference in mpg when it isn't at operating temperature. Never cared about the coolant as it gets heated up very quickly.