The rear filter is a complete PITA, I just run without the cowl (leave hvac filter on) and ziptie the cable lines down, it makes working in the engine bay 10X easier. Terry's been running it like that since day 1 with no issues, and the cowl is just a big heavy piece of sound-deadening plastic so far is I can tell. Not to mention the DCI sounds awesome without the cowl, though that's a matter of preference. Stock box to DCI is a 15 minute deal now, but the first time I did it I left the cowl on, took me about an hour to seat the rear filter. That was MISERABLE lol.
E88 N54 Alpinweiss/Coral Red/Motiv HTA 3586R/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 FCA + Tension Rods/M3 Subframe Bushings/M3 FSB/DINAN Camber Plates/Apex ARC-8/Project Kics/VAC Hubs/Rogue Transmission Mounts/Alpina TCU Flash/Icarbon/Kerscher/BMW Performance