Ok, i have two 12" (07C124) Kicker Comps With A (XM-GTX1852) 1000 Watt Sony Amp Pushing Them.?

My Question is what can i do to get the most and loudest best bass out of the subs. cause i got a friend that has two 12" Red sony xplod subs, and a ( LA970 ) 1200 watt legacy and his system rattles things in my house. mine is no where that close. and mine is no where near as loud as his inside and outside the car. i thought kickers would be a lil better than sony xplodes? both mine and his subs are in sealed boxs.