Woof. Looks pretty nasty. Could be ok though. I purchased a throttle body from a scrapped SH-AWD TL that had been sitting for quite a while and it had the same white buildup. I polished it up and the white crap came right off. So I don't believe it's corrosion. I think it's just mineral buildup of some sort.

If it's cheap, I'd say go for it, then spend some time polishing it up. Get off as much of the white buildup as possible. Probably the biggest thing would be to remove any loose material before installing it so none of that crap gets into the engine. Although the manifold looks like it comes apart at the seams, there's some sort of adhesive in addition to the screws that hold it together. So getting in the inside is kind of a no-go. Do the best job you can and I think it would be fine.

 

That looks corroded as hell man.. maybe water got into it and ate away and the white is just calcium deposits.. Can you still mate a TB to that port? It looks eaten away

 

Yeah, if you start polishing it and notice pitting then I'd pass on using it. But if the deposits wisk away and it's shiny and smooth underneath then you'll be good.