I would be surprised if a muffler added any power. Maybe 1 or 2 hp if you must be optimistic. Hopefully it doesn't cause any loss of power! I'm not sure if my Eisenmann Race made any difference plus or minus, but sometimes I feel that my car does not accelerate as fast ever since I installed the AFE filter.
2012 Audi R8 V10, 6MT, Suzuka Gray, Larini Clubsport exhaust, Klassen M52R, GMG springs, Satin Black badges
2012 Audi A6 3.0T Prestige, Moonlight Blue
2014 BMW 528i, Space Gray
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