I have a 98 YZ400f and need a spark arrestor. My budget Is minimal it seems my choices are an end cap with a insert to silence it, or a FMF Q series pipe. Can anybody let me know if the silencer insert works well, and how much power does it rob and is there re-jetting required? And does the "Q" pipe work well and really give more power than stock, at the same time make less noise? And is there re-jetting?