The new 2.8 turbo in the 9-3 Aero is made in Australia by GM's Holden division. A 9-3 Aero with the automatic is built in Sweden with an Australian engine and a Japanese transmission. Weird eh?
The 9-3 and 9-5 both come from the factory with Mobil 1 0W-40 I believe. Not sure about the 9-2X or 9-7X, as you said they're really a Subaru and a Chevy, respectively.
Reliability on the 9-5 is quite good, it's got a couple of "issues" as they say but nothing major. Solid car. The 9-3 doesn't seem to have any real problems either, though early models look to have had some electrical things.
jeff