Well to follow up on this thread a bit,
So I ended up replacing plugs, and the fuel filter. Noticeable improvment. Plugs looked pretty tired, and the fuel filter did too. But from what I was told, only the outer filter (white plastic part that clips in to the basket) was available. There was a bunch of black crap on the filter sock itself, but that part is not available, so I cleaned it as best as I could. That may be the next avenue. Also another thing I noticed was a hairline crack on the inlet chamber, just before the throttle body, so it would have been sucking unmetered air in. Tried plastic glue, but may get the crack plastic welded at some point. If you have a bp shape 3.0, I'd check for this crack, seems to be a common problem according to the aussie forums.