If you just want noise from your E46 M3 (but no drone) then a custom build catback is your answer. Drone has always been the issue on the E46 m3 but with our custom build exhausts we have fixed that with our own unique design. By adding a pair of absorption silencers (no baffles, no airflow restriction) we have both kept the power gains and reduced to the drone to zero.
We do two versions – loud and quiet, depending on your tastes and a catback can be later upgraded to a full system for full power gains if required.
We custom build in house at our workshops near Silverstone, TIG welded, mandrel bend for full airflow with an option of tip choices including our own carbon fibre versions (extra cost).
Type 304 stainless steel throughout, full lifetime warranty and of course price includes fitting.