The Jaguar's 4.2 does only 300HP (and initially 280HP when introduced) in naturally aspirated form and used the blower to get up to 395HP, so I'm led to believe the 4.3 of the Aston not naturally aspirated if it produces 380HP

And judging by this picture of the Astons engine, it looks like it has a supercharger on top of it (the first thing I though when I saw it is how much it reminded me of the Jaguar XKR's 4.2 supercharged V8 before I even knew it was derived from that engine)