I read the following on motorauthority.com (http://www.motorauthority.com/alfa-r...a-coupe.html):
There will be one new turbocharged petrol engine that will sit in the middle of the 159's engine range, as well as a new turbodiesel that will be replacing
the existing 150hp (112kW) 1.9L diesel unit that currently resides in the lineup. These engines will eventually be making their way into the Alfa Romeo Brera and the Alfa Romeo Spider as well.
The new turbocharged petrol engine will have a displacement of 1.8L, and thanks to the aid of forced induction it will output more than 200hp (147kW). This engine will be replacing the larger 2.2L naturally aspirated engine found in the 159 and Brera/Spider, which only manages to put out 185hp (138kW). Along with more power, the new turbocharged petrol engine promises to use less fuel and emit less CO2, and if estimates are correct than the engine should help push the 159 to 62mph around a second quicker than the current engine, while bringing mileage up from around 25mpg to 28mpg.
Meanwhile, the new 2.0L turbodiesel unit will boast around 170hp (127kW). Early drives of the new turbodiesel undertaken by Auto Motor und Sport suggest that the older engine was actually more refined and still featured more than enough torque for the Alfa Romeo's purposes.
Both new engines, however, meet Euro 5 emissions standards and will be cheaper than the current engines found in Alfa Romeo's lineup. The new turbocharged petrol 159 is expected to retail for around €25,000 ($34,900) in Europe, a saving of around €4,000 ($5,500). Official pricing should be released for the full range closer to a launch in the third quarter.