The Givi's are tuning forks. They vibrate. I have found you can tune them some by loosening them, slightly move them and retighten them etc. This can help, and put a peice of rubber hose wedged into the hole in the fairling,a nd wedge it in between the guard and the fairling.
I have a Devlin skid plate, made in Portugal. I really like it, smaller and lighter than the others, but rugged. Tis isn't my dirt bike, (I have a DRZ400) but it gets bashed anyway, and has stood up well.