[07+ 328i] How well does the stock muffler flow? Custom Midpipe?
On some cars I've worked on, the stock muffler flowed fine for quite a bit more HP than the car made. It was the midpipe that was really restrictive. Was curious to know if BMW is similar.
Has anyone replaced only the down/mid-pipe with say a 2.25-2.5" mandrel bent SS unit? The reason I say down-pipe as well, it'd remove the cat/res - it'd be cheaper and flow better.
The only concern is noise, this is practically a straight-pipe (till stock muffler) so it might be deafeningly loud.
A cheaper alternative perhaps? Thoughts?
02.tw.ep3 [Civic SiR]
jdm | 04.itr.suspension:22mm.itr.rear.sway
Looking for a e90 soon!