Originally Posted by Johnny D
I ignored his comment because he has the n53 euro motor and this doesnt apply to the US spec cars. Also, if he wants to ship me a set of the n53 manifolds Ill pay shipping, cut the cats out and do a dyno comparison.
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).