Replaced old kicker 12" sub (damaged during my house move) and took out the 250w kicker amp.
Replace with an infinity 2400w 12" with a carbon cone - and a black widow 1200w digital mono amp. Had to reset everything on the headunit, first it wouldn't hardly work, then I played about with the gain and the amp settings. So it's all good now - also moved the box over an back a little to mount the amp on the back of the box.