well my mag seems alot louder than my xxx but then again my xxx was a 12" and the mag is a 15" //content.invisioncic.com/y282845/emoticons/naughty.gif.94359f346c0f1259df8038d60b41863e.gif
This really wont have any full bearing on the vs. question, but...
My 2 12" mags on a 20.1 in boxes that were too big hit a 149.6 with no tuning. Just threw in a pair of areo ports, didnt try and tune it. Oh, in an xterra
A friend of mine is hitting 148-149s with 2 12" XXX and 2 Hifonics bd1501's in an explorer.