[awawd335]

I am considering getting downpipes for my 335xi. An old post from Hotrod made me wonder how significant the gains really are (he suggested he didn't see much in the way of gains on vbox testing for his 2.5 in catless pipes).

Everyone seems to quote gains of around 25 hp for catless downpipes (with a tune). I searched for quite a while, but the main data I have to support this fairly significant gain are either from butt dyno or from a downpipe purveyor (I'd like to see an independent source if possible).

Does anyone have before/after dynos or drag times for their downpipes? Thanks in advance if you do.