Impossible to go wrong with Two-Brothers. Installation is literally only a few minutes and you're good to go. Just make sure you've the proper o-ring selected and you shouldn't have any wiggle room at all.
Many municipalities and tracks have implemented new, tougher regulations that limit the sound output of street bikes, off-road cycles and ATVs. Two Brothers Racing has developed a series of highly effective sound reducing tips which can help you be compliant.