depends on what your perception of loud is. Some say its loud but i think its a medium at best. Just be sure to unplug the mic in the back of the headliner.
Highway speed there is a little drone but not really noticeable unless you have the radio off and windows up.
if your looking at the mbrp check out the race version. I have it on mine and it sounds great. From the videos and everything i looked it showed the street is about as loud as the race just not as deep.