Headers?
I have used tti headers.
Once with 340 j headed tti headers (headers came with the basket case)
Ran w2 tti headers for a few years on the stroked 340 (418) with the 1 5/8 headers.
Now waiting for the 1 7/8 w2 headers for the indy headed 418.
I have never had any issues with tti headers yet. Never had to dent or modify them in any way.
I also run tti x pipe full exhaust system with their mufflers. Everyone seems to love the sound of my car and I always get compliments.
I cannot compare any other header as I have never used any other brand.