Originally Posted by BudVlad
Later version of N52 has the same manifold as N53. There was a thread by someone who is racing 328i and he is using OEM catless manifold.
BTW: the OEM manifold picture is from Penske parts catalog (N52).
I remember that thread too. I could never find it again either. All the manifolds I have seen have the same collector as the one on the right.
I have not seen a north american car with collectors like the one on the left in the pic. Anywhoo. No one has dyno'd these mmw headers yet. I don't think I have seen a dyno of supersprint before either. All I have seen is dimsums dyno of the primary delete with 15whp gain. I just bought a stock manifold and it is en route to me from NY. Once I get it I will delete the cats and dyno. I already have a baseline so I think it will be a good reference.
Your headers look mig welded, are they?