Yeah, the Alfa V6s are nowhere near as efficient as newer engines. They're also well outdated re performance/consumption, as I've raved on about in other threads
Other examples of big performance cars with lower CO2 levels than a 220PS, 3 litre V6 Sportronic are shown below and demonstrate how much more efficient the newer engines are...but then you won't be able to buy them for a few grand!
BMW M3 (420PS, 4 litre V8) 295 CO2 g/km
BMW 550i/650i (367PS, 5 litre V8) 260 CO2 g/km
Jaguar XF Super V8 (416PS, 4.2 litre V8) 299 CO2 g/km
Jaguar XJR (395PS, 4.2 litre V8) 289 CO2 g/km
Mercedes S500/CL500/SL500 (388PS, 5.5 litre V8) 279 CO2 g/km
Porsche 911 GT3 (415PS, 3.6 litre F6) 307 CO2 g/km