I actually thing that the Twobrothers exhausts offers the most bang for your buck. They have a deep throaty sound and are super lightweight (I used to have the on my ZX7-R). Their an oval type slip-on so they are less closer to the panniers (so less mud accumulation when doing so major mud. Off-roading. They offer different models: aluminum for 360 CAD/USD, titanium for 100 more as well as carbon fiber in black(for about the same as the titanium ones) go check em out and tell me what you guys think!