ETS 5 inch is extremely high quality and perfect fitment. I installed it myself. Zero trimming. Has an N55 specific pipe. This IC costs more than some low cost options but is extremely popular and well proven across N54 and N55.
Koni sport, BMW performance springs, M3 arms and sways front and rear, M3 subframe bushings, Velocity toe arms, M3 front strut bar, Cobb, ETS FMIC, Vishnu charge pipe, RPI scoops, M3 steering wheel, City Vision angels, CDV delete, Advan RS 18 inch, Pilot SS