I do some average stereo systems for my buddies.but I want know what u guys would think about 4 or 6 kicker comp 12s in a explorer if it would be like house shaking and also would it be better to add something to my already sub I have a Rockford fostgate 12 inch t2 if I built a better box for it it's in a shitty box right now but how big of a box should I build for it thanks everybody