GG header vs KTM/HUS header

I recall seeing in some tests where the testers sometimes said they either couldn't notice a difference or even preferred the GG one. I wouldn't expect to notice much difference if I tried them back to back. I will say the KTM/HSQ one will burn the crap out of your pants if they are not leather inside the knee

That resonance chamber is supposed to make the exhaust a little quieter.

On the 250 the biggest difference I can see is the KTM header is a little less snappy off idle. Depending on whose dyno (Dirt rider) you look at the GG header has a big hole in torque on the 250 at low rpm. You don't see this on the other dyno comparisons though.