What is the difference in quality and flow from brand to brand. I understand the merge collector, most headers from various brands seem to be almost identical, 304 stainless steel, equal length etc., so whats makes one better than the other?

There also seems to be a big difference in price from one brand to another.

I am looking at:
fabspeed
Dansk
Schnell
B&B

Any insight or first hand experiences would be great. I have a 2002 C2 996 Cab.

thanks in advance for the feedback. Ted