Originally Posted by ozinaldo
This is interesting; so when you analyzed the exhaust for the 1M you came up with the conclusion that the downpipes are different and less restrictive than other N54 applications. Can you further comment, to what extend they are less restrictive? Is it still advisable to upgrade to let's say AR 1M down pipes or maybe it is not very cost effective because of minimal gains? I am not only talking about as a requirement for the tune.
it is certainly an interesting observation
since we are talking about OEM downpipes it still has to abide by emission laws for US, even if it may be slightly less restrictive
so I think you'll still see an improvement by switching to catless downpipes