Measurements of the Akrapovic EVOLUTION system on the APRILIA RSV4 (without muffler insert):  Power & Torque: The power increase with the Akrapovic system is substantial, and can be seen from 4800 rpm right to the top of the range. At 12450 rpm we measured 168.8 HP, with a max. power increase of 6.4 HP at 6790 rpm. The system?s effect on the torque and power curve is huge and strongest at midrange rpm. The main increase starts at around 4200 rpm and continues right into the over-rev range. All this will help you shave lap times and result in a much smoother ride.