Hi.
Long time no post for me. However, if you're still looking, I had Moretto Motorsportz do my Corsa Sports. I dealt with Ryan--very professional, and if you go there, you will see some BOSS cars in their bays. They did a nice job.
I'd recommend getting some headers and high flow cats with the Corsas. Then you have a lifetime warranty stainless steel system. The only future exhaust issues you might have would be to replace the cats. The extra power and sound was well worth it. I've mentioned this elsewhere on the forum too--this has easily been my favourite mod on a fairly heavily modded C6. The bonus was that Moretto happened to get me Corsas at the best price I was able to find anywhere as well.
Good luck--either way you'll love the Corsas. If you ever want a dose of the, before buying, look me up in Edmonton!