They are "C6 LS2 exhaust manifolds" if you look for them. They sell for about 100-125 dollars a pair, shipped, over on CorvetteForums, and when I put up a WTB over there I got like 10 offers in 3 days. Easy to get at.
I have two cars in my garage with turbo kits VERY similar to the one Zac has. They work really well.