If DPs+berk mids+Eisenmann race isn't loud enough for you...man you must really want it LOUD. Berk race is a muffler delete so it will certainly be louder, but it will also drone more. The resonated mids handle rasp very well, but the drone could be pretty intense esp. if you're 6AT. Berk is a good company though (see my mods), many people here run Berk race and seem very happy with it. You could sell the Eisenmann and have a good margin for a diffuser after getting the Berk setup.
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586r Tial .82AR/Motiv Port Fuel/Meisterschaft Race/Berk Resonated/ER CP/Synapse/VRSF FMIC/Rob Beck PCV Valve + Cap/ST Coilovers/M3 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/AA Strutbrace/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance