i would think that the acm oem exhaust is louder since that is a straight pipe. the perf oem mod is probably louder also.
2013 X3 XDrive28i - Stock
2008 E92 M3 SG DCT Extended - AA Filter, JL Audio 600/6, CDT Audio, Verstraβe Paddles, ECS SS, BMW Performance Spoiler, MH race studs, BMW GTS wheels, Stoptech ST, AP CF Intake pipe, MS Pulleys, Eibach, MR Exhaust, BPM Tune, LTBMW 1M Bumper, MotoGP Lip, Euro MDM, LCI's , KW CS, TMS Soild Diff Mounts.
2008 Porsche CS - GT3 kit, Sprintbooster (SOLD)