Coby, what's a Buzzells? Is that an auto parts store? I don't think we have those here in the US. I've tried NAPA and they don't have it (and can't get it) either.
By the way, I send an email to your first link (buyautopartsonline.ca) and they came back saying they don't have it either, and can no longer get it. I've spent the last three days doing Google searches for this part, calling every place that said they had it, and not one actually did. The local GM dealer did a national search on 10359640 and none showed up, but he didn't do Canada or Mexico. I guess their system only works in the US. But he basically said that if he can't find it in the US, it just doesn't exist.
That's way I'm trying to find out what the differences are (if any) between the 05-08 valve and the 09-10 valve. We got the 09-10 valve yesterday and compared it to the 05-08 valve, and they're exactly the same externally. Internally, we have no idea, but unless it's a ratio change from the original 60/40 to something else, I can't see why a new part number would have been assigned. Heck, even the bracket is the same!
GM only assigns new part numbers if there's a change made to the part, so there has to be something internally that's different. That's what I'm trying to find out, but even the service manager at the local dealer doesn't know. And there seem to be no notations in any of his books on what the differences are either.