Gen 3.  3 SGE. Up till about 1996 I think was 4-2-1  From there on they were 4-1.

Thanks for clearing that up Falcon
What a great source of information this forum is!
 
 

Is there anything Doug doesn't know?
I bet he's forgotten more than i've ever learned lol.

Would this explain the slight power drop from post 1996 Australian Delivered SW20s? 1994-1996 were rated at 129kw and the later ones at 125kw.

mister_two
Would this explain the slight power drop from post 1996 Australian Delivered SW20s? 1994-1996 were rated at 129kw and the later ones at 125kw.

 
I think it was probably pollution gear related, to conform to stricter regs. 
 
But generally  4-2-1 = more low down torque
While 4-1 = more top end power

Yep. Spot on as always Red. 
They got exhaust gas recirculation, coupla otha things an a different computer.
And a significantly different exhaust sound.  My 1996 car with the same cat back exhaust as I have on the later car now used to have an annoying whine.  Whereas with the 4 into 1 She actually likes the exhaust note.  Even the splots and splutters on down changes.

Ahh thanks Red and Falcon! Some things to think about when I get my custom b-pipe made for my G-Limited.
I recently purchased a Fujitsubo Super EX to modify for my BEAMS engine, then a week later I found (after a 5-6 year search) a Phoenix's Power (Garage Fukui SPL) exhaust manifold in Japan.

Hey Darren. Please post up your thoughts once you put that exhaust manifold on your BEAMS. I'll be fascinated to hear if it makes a noticeable difference. Maybe I'll have to start a 5-6 year search for one too!  

Falcon
Yep. Spot on as always Red. 
They got exhaust gas recirculation, coupla otha things an a different computer.
And a significantly different exhaust sound.  My 1996 car with the same cat back exhaust as I have on the later car now used to have an annoying whine.  Whereas with the 4 into 1 She actually likes the exhaust note.  Even the splots and splutters on down changes.

Interesting about a different exhaust sound with the different header configurations.
 
When running an aftermarket cat and catback with the stock header system on my gen 2, I had an annoying drone around 100 kph on the freeway. As well as that the exhaust was also just a bit too loud.
Then after I fitted the the Super X set, not only had the drone completely gone but the exhaust was noticeably quieter. So win-win.
 
 

Falcon
Gen 3.  3 SGE. Up till about 1996 I think was 4-2-1  From there on they were 4-1.

 
I've just done lots of digging about and confirmed that they were 4-2-1 all the way through to the end of the 3S-GE's.