E93 has exact the same exhaust as E92.
The E90 has a resonator in the X pipe, so it is less loud.
The passenger side muffler contains big resonator so it is quiet.
The drivers side muffler contains this kind of cat, in fact it is a small resonator that gives the nice sound when the flap is open.
I whould subjest only to remove the rock wool inside the mufflers, and close them.
It should give a nice sound