I just got my set of Hedmans in from Summit, and to my surprise they have a different style collector on them than the set I got 6 months ago for my current setup. Apparently, they are gasketless flanges, much like the stock manifold to the stock cats type flanges. Overall, the quality remains the same on the headers. I already see the flange warped which I'll fix, the paint is already falling off, and the welds are crappy. But, for $125, they are a steal still. Just thought I would share the news. The flanges are a much imporved design that will allow for that little bit of alignment imperfection from different manufacturers of exhaust products.
On a side note, now that I have normal headers, anyone in the Phoenix, AZ area have a stock LT1 exhaust they want to get rid of, really cheap.

I'm not too concerned about mufflers, I was planning on buying muffler eliminators to sell the car with, but if you have them and you're close to Phoenix, I'd be happy to take them off your hands and in the process, help clean up your garage.