I've got a Passat SE estate 2.0 tdi; I get 48 mpg from it and the CO2 is 156gms/km. It's fantastic on long motorway runs especially as cruise control is standard. It cost about £5000 less than an A4 but it's bigger inside. With the rear seat 70% folded we can fit our son and 3 bikes inside, dismantled. With both seats folded I can roll my bike in without removing the wheels, which is great for evening club rides. Don't go for a black interior, it shows all the dirt and fluff; go for grey.
I never understand people with estates, vans and hatchbacks who stick their bikes on a rack outside the car. Mad.