Welcome Spider. Agree with Chindley, you always get more negative than positive posts. I'm really pleased with mine.
As for 2WD, there really shouldnt be any difference, as the AWD is in 2WD most of the time, the 4WD comes in only when needed and the front wheels slip. Which to be honest, I had to drive like a maniac in the snow last year to make the front wheels slip, just to experience the 4WD, as the torgue on the front wheels (and weight) was enough to drive comfortably in the snow. Mind you the AWD did give you that confidence that it was there if needed. Living in South Wales I found the Hill Decent of more use in the snow, not sure if that is only onthe AWD models or not...
Anyway, back to your question... Try eBay, have seen the rubber boot mats for around £20 on there. You'll need to search for them as I havent any links sorrry.
Hope you get a positive feeling from being a Captiva owner like most of us have...