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      12-29-2012, 11:44 AM   #18
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gatorfast's Avatar

Drives: 528i M Sport
Join Date: Jan 2008
Location: SoFla

iTrader: (3)

Originally Posted by Munit View Post
I had the OEM ACM mod and it completely drones loudly as the OP stated. Unfortunately it is the absolute worst cruising at anything above 69mph on the freeway. Totally had enough. Went back to OEM rear with high flow cats and the sound not only got better but the drone completely went away.
Yea that's not the same thing we are talking about here. The ACM mod is essentially straight pipes which is much louder and drones compared to the traditional oem mod (replacing two perforated pipes).