Since you have an E90, the Morels will fit with just the adapter. The BitOne can accept balanced diff inputs. It could not handle the speaker level outputs of the EPS amp so an intermediate LOC had to be used. From what I understand, the Morel tweeters can be installed in the OEM tweeter location without modifcation.
09 E90 M3 - Interlagos Blue / Black Novillo / Sycamore Anthracite / Eibach / HRE