Give me your standard exhaust manifold and I'll compare it to my TRD copy extractors and tell you what the difference is
Seriously though, let me know if you sell the manifold and I may buy it off you.
I have ae86 so I can't comment on fitment in ae71, and I also can't compare to other exhaust manifolds as this is the only one I have used. It seems to work fine, but I'd like to HPC coat it and heat wrap it when money allows.