I'm doing a 143+ on termlab in Street Beat on a single DD 9510 in my Saleen....So if your not even doing a 140...I'd say yes a single good quality sub will be louder....At one show I was running 4 DD 1508's and was louder than 3 vehicles I know of that ran 4 15's each...one was CVR's...The other was RE SX's....I'm not sure of the 3rd on brand....another show with 2 DD 3510's in the hatch...I was louder than a Hummer H2 with a ported wall of 4top of the line RF 15's.....I'm not sure about other brands of subs...but from my experience DD's are the loudest subs made....//content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif