Hello, I've got a CMD 102P with a Fender Jazz Custom Classic and am very happy with the sound I've got. I am, however, looking for an extension cab for louder gigs. I like the Markbass Traveler 102 cabs, but what's the difference between a rear-ported cab and a front-ported cab? I remember reading somewhere that most players match a rear with a front, but I really have no idea. I'm also looking at the 15" Traveler as I'm looking for deep lows, something to shake my feet. If I add another 2x10, will I get more punch and overall loudness but not sub-tones? Conversely, will the 15 simply add low end to the combo? I'd like to keep the punch and clarity of the combo, while adding more volume and more low end.