The best and cost effective way would be to change the gearing. Its recommended to change the rear sprocket before the front. For every 3 teeth in the rear that is about the equivalance on one tooth in the front. to tame the low end you would use a smaller sprocket on the rear sprocket or larger in the front. If you want to significantly tame it down, go up one in the front and if not go more. Front sprockets only cost approx 30-50 bucks depending on the brand. But remember by doing this you are increasing the top end speed. On my banshee there is also a throttle limiter screw on the stock throttle housing when i had it on that you can turn in that restricts the allowable throttle, acts as a throttle block. I am not sure if the raptors have this.