Finally there is some news about the facelift. Because the article is in German and probably not everyone can read it, I've made a quick translation (just a summary) in English:
Four years after its debut and a production of nearly 1.500.000 cars worldwide, Alfa Romeo renovated the 156. Changes are all under the metal and the exterior stays the same. The performance of the car has improved, so are the safety features. The new 156 will be available on the 16th of march in Germany. Prises are not known yet.
New Petrol engine:
2.0 JTS: 121 kW (165HP) at 6.500 rpm and 206 Nm at 3.250 rpm. Topspeed 137,5 mph and 0-62mph in 8.2 sec.
New Diesel engine:
2.4 JTD: 110 kW (150HP) at 4.000 rpm and 305 Nm at 1.800 rpm. Topspeed 132,5 mph and 0-62mph in 9.4 sec.
The new Alfa 156 has more safetyfeatures. VDC is available on all models. ASR can prevent blocking wheels at sudden downshifts. Xenon headlights are available as well.
Every model will have head-airbags and Isofix for childseats
The airco is like the one in the 147 with separate temperature controls for driver and passenger.
Other new aspects are: Rainsensor, Air Quality sensor, Cruise control, Boardcomputer, Connect. The armrest in front comes as a standard feature.
Upholstery is new as well. The dasboard is redesigned.
You can look at the article at http://www.auto.t-online.de/