I have the ATS manifold on mine and am fairly happy with it. Its built tough and made to last and so far in the 20k its neem on my truck it has worked fine. The only complaint I have with it is their TERRIBLE heat coating that disappears and allow the manifold to rust on the outside bad. IF I did it again I would go to High Tech Turbo's and have them HPC coat it before it came to me.
I am not sure there is much difference between the three manifolds,ATS,HTT's and B-D's for power and it more a personal favorite choice to me. I went ATS because the shop who did my work stocked them... ... ... Andy