This has come up before. Apparently, Volvo contracted Porsche

to do the original design. I suspect Volvo has engineered the

changes since (head changess, variable valves, different turbo

configurations, etc.). I guess contracting like this is fairly

common. As an example, I read somewhere that engineering services

to other car companies are Lotus's main revenue source.

I also have to agree that it is an impressive engine. A nice

size to serve many markets around the world and still plenty

of power/fuel economy. Reliable, too.