When my exhaust header cracked, it was where each tube joined another tube. There were several cracks and they all opened up slightly. Welding the manifold may cause it to distort as the welds cool and the cracks draw in. It is worth trying before spending the money on a replacement.
The Aerio header will not work in stock form. It would require rerouting the outlet. DWR can make a replacement, but I don't know how much it would be.
I have the Hurricane header discussed earlier in the thread. I was fortunate enough to have it carried back as a free checked baggage, so I didn't pay shipping.