my thoughts are limited to the E46 M,
Like Oscar said, there is very little that can be done to the standard setup, I've been looking around and researching various international forums and while many say that after market induction does help, there are those that refuse to change it, while the scale leaning towards keeping it stock.
However, the only piece that I'm looking to change is possibily the elbow, the aftermarket one seems to allow for better flow.
M3ance (on this forum) and I have simliar mods with the exception that he has the full K&N induction, on the same dyno (different time of the day), he made roughly 1 kw more than I did.. I really don't think the cost of the kit warrants 1 or 2 kw increase, however I also understand that the inductions are also suited to higher speed driving, that where you should see the difference. M3ance and I are yet to test this theroy
