Originally Posted by gatorfast
Trust me there is absolutely zero drone with the OEM mod. OP is the only person I heard of to report any drone with this mod. It sound probably 90% the same inside the cabin with only an increase in volume when you really get on it. Cruising on the highway it will sound the same as stock, no drone at all. The real increase in volume is on the outside of the car.
Thats the beauty of this mod. Outside it is much louder than stock and sounds aggressive but inside it sounds almost exactly the same.
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.