A few thoughts..
1. All three choices are excellent, theyll all produce wonderful tone and you wont have any issues with fitment. Thosr are 3 of the highest quality options out there imo.
2. you do NOT "need" aftermarket mids to make any of these systems sound great, its just a supplement that puts it over the top imo. Sus gt with n55 mids will sound awesome.
3. If i were choosing between those and cost was not a primary concern, id go eisenmann. Akra is the only company with higher quality stuff, maybe kresseig.
4. Im getting my car back from the shop this evening, by weeks end ill get you some gopro footage of the car under wot and other conditions.
E88 FBO N54 Alpinweiss/Coral Red/Meisterschaft Race/Berk Resonated/Macht Schnell 3"/ER CP/Synapse/VRSF FMIC/FFTEC LPFP/HFS-4 DO Stainless Lines/BMS DCI/BMS Thermostat Delete/Rob Beck PCV Valve + Cap/BMS OCC/PTF E50/ST Coilovers/M3 Front Control Arms + Tension Rods/M3 Subframe Bushings/M3 FSB/DINAN Camber Plates/Apex ARC-8/Project Kics/Macht Schnell Studs/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance