Akrapovic Racing and Evolution systems are designed for riders who demand maximum performance from their motorcycle. Both systems are significantly lighter, if compared to the stock exhaust system and feature exceptional production quality, hi-tech materials and of course increased engine performance combined with pure racing sound output. The Akrapovic Racing and Evolution systems were developed to complement the racing character of the RSV4. The Evolution system is made entirely of our exclusive high grade titanium while the Racing system uses stainless steel header tubes and link pipe. We offer titanium or carbon-fiber mufflers for each combination. Both systems are not street legal and are designed for racing purpose only. 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.