My bike had Cobra slash cut slipons already installed on it when I purchased it. I ran these pipes for a while, but I felt that they were a little too loud and it seemed like the bike would wind out quickly and would not build any additional power with increased throttle input once it hit a certain point. Therefore, I saved for a new set of V&H slash cut slipons. These were not as loud and seemed to let the bike build power longer with increased throttle input. I theorized that the Cobra slipons were less restrictive then the V&H slipons and that the perceived difference in performance was due to the bike needing a certain amount of back pressure in order to perform well and that the V&H slipons provided the right amount. I am not sure if my theory was correct or not, but I have been very happy with the performance of my V&H slipons. However, I wonder if a full aftermarket exhaust would be even better than the V&H slipons or not? If so, is the difference in performance worth the difference in cost?